Where the Beer Goes to Foam: Experiments in Beer Foam Chemistry and Considerations of its Future Potential

See my video of the results here: http://www.youtube.com/watch?v=emqUMFYsfIg

Introduction/Motivation: I just obtained a Pressure Whipper, and want to figure make an appealing beer foam for use in a variety of culinary situations. Several people online have posted various methods for making cocktail foams, and I found one person that attempted a bourbon barrel aged stout foam. The critical ingredients were: beer, egg whites, and sometimes gelatin. I varied the amounts of these ingredients for this lab.

Literature Review:

(unless otherwise cited, taken from the Science of Cooking by Harold McGee, covering any section that mentions gel, gelatin, and foam) (and no, that’s not an acceptable citation for any rigorous report, but being that I’m not getting any real credit for this, I figure that’s good enough).

Definitions:

Dispersion:

Dispersions are mixtures of two materials that are generally evenly mixed.

Gel:

Gels are liquids thickened with molecules. Unlike starch thickeners, however, gels are typically translucent due to the small size of the thickening molecules, either proteins or carbohydrates. These molecules don’t thicken and separate like starches tend to do, either. Gelatin molecules are proteins that expand with the addition of heat, and then bond to each other during cooling. They then set, or combine in a stable network of interlinked molecules, forming a gel.

Emulsion:

An emulsions is a liquid thickened with other liquid droplets (e.g. mayonnaise).

Suspension:

A suspension is  solid dispersed into a liquid (e.g. coffee).

Foam:

A foam is a liquid thickened with air bubbles. Air bubbles disperse through the liquid and form a thickened, foamy product. The air in a foam interrupt the flow of water through the foam, allowing it to hold its form for some amount of time. Unlike gels and emulsions, foams are more effervescent and ‘live’ for a notoriously short amount of time. They tend to crumble under the force of their own weight in the presence of gravity. Gravity ultimately drains the liquid from the bubble walls, thinning the bubbles until then inevitably pop.

There are two main ways to delay the ‘popping’ or collapse of a foam. First, you can thicken the fluid with “truly substantial” [McGee, 595] particles or molecules (e.g. oil droplets, egg proteins) to physically slow the fluid drainage from the bubble walls. Second, you can add emulsifiers (e.g. egg-yolk lecithin) that can stabilize (i.e. strengthen) the bubble structure itself. However, it’s important to realize that foams are desirable because they are light and airy. Too much of a “substantial” addition or too much emulsification will negate the very purpose of a foam.

Foams are most simply stabilized by whipping air into the liquid. The addition of air to the liquid in the foam increases the surface area exposed to the air. This increases the ability of volatile aromatic compounds to release into the air producing, ideally, a delightful aroma.

Other ways of combining air bubbles with a liquid include foaming wands (i.e. what you get in an espresso foam) and the use of foaming devices that pressurize the liquid with CO2 or N2O.

No matter how you get the gas bubbles into the foam, if it is simply some gas and some liquid, you will create a very short lived foam (watch the lifetime of a latte foam to get some idea). The addition of emulsifiers (e.g. lecithin, protein) can extend the lifetime of the foam. Emulsifiers generally have a hydrophobic and hydrophilic segment. The hydrophilic segment extends into the water and water soluble portions of the foam, and the hydrophobic segment extends into the rest. By separating the two inherently insoluble portions of the liquid, emulsifiers prevent, or at least hinder, the inevitable mixing. The end result, to our delight, is a longer-lived foam.

Inevitably, however, any foam will eventually collapse due to the action of buoyancy. Even with sufficient emulsifiers, any air within a foam will float on top of any liquid, and and liquid will sink beneath the air in the bubbles. When the bubbles reach the top, they will dry and pop. When the liquid reaches the bottom, they will mix and form a gasless liquid.

Even yet, there are ways to delay this inevitable collapse. The addition of starches, pectins, gums, and even emulsified fats will slow this separation of the liquid from the gas. Generally, fat is a ‘foam killer’ [McGee, 639]. But, if the fat is emulsified (i.e. covered in egg yolk), the fat remains dispersed in the water phase, and the fat droplets are hindered in their ability to pop those delightful bubbles.

Foams can also use surfactants to elongate their lifetime. Surfactants reduce the surface tension of a liquid, which affects the amount of pressure that can build up in the air bubbles before they pop. [Kevin Liu]

Cocktail foams, like all foams, contain a dispersed phase (i.e. the bubbles) and a continuous phase (i.e. the liquid). Altering the composition and fraction of these two phases affects the final foam. Specifically, they affect the creaminess and viscosity of the foam. Creaminess can be achieved by creating many uniform bubbles of the dispersed gas. If the bubbles are all below 30 um in size, the tongue can no longer tell the difference and the foam takes on a creamy texture. Viscosity is affected by the dispersed phase bubble size and the viscosity of the continuous phase.

Agar-Agar:

A carbohydrate that acts like a gelatin protein. Agar (short for agar agar) is a mixture of several carbohydrates that are extracted from red algae. Agar solidifies at ~ 1% by weight, compared to gelatin which requires ~ 1% by weight for solidification. In general, agar is more crumble than gelatin, and sets around 110F/38C. However, agar won’t reliquify until it reaches 185F/85C (gelatin sets and reliquifies at the same temperature, ?F/?C.

Gelatin:

In the US, mostly manufactured from pigskin (and sometimes cattle skin and bones). The industrial process is very efficient at extraction, resulting in sheets or granules that are 85-90% gelatin, 8-15% water, 1-2% salts, and 1% glucose [McGee].

Both sheets and granules are soaked in cold water first so that the gelatin network can absorb the moisture and dissolve readily when warm liquid is added. If this cool liquid soaking is skipped, you could get gluey and clustering of individual or chunks of gelatin molecules [try this?].

Powdered gelatin can be used to make foams. Just use a 1:100 weight ratio for gelatin:liquid. Add these to a pressure whipper, and chill since the colder the foam the more stable it will be. Will it ever form a gel in the pressure whipper? [Kevin Liu]

Xanthan Gum:

Xanthan gum can be used at a 0.5:100 to 0.8:100 weight ratio. Just make sure to let it rest for at least 5 minutes in the whipping siphon. [Kevin Liu].

Background Research of RECIPES:

Dark and Foamy:

(http://www.youtube.com/watch?v=dWwQSkwSvKc)

The cocktail:

40ml Pampero White Rum

20ml lime juice

10ml simple syrup

4 dashes bitters

The foam:

1 can ginger beer

100ml Kraken Rum

dash of lime juice

gelling agents (cellulose powder and xantham gum) - proportions not specified!

The procedure:

1. Mix the cocktail

2. Put all the ingredients for the foam in a pressure whipper. Shake to mix. Add 2 packets of N2 (sic).

Barrell Roll - Beer, Foam, and Bourbon

by TWDIndustries, http://imgur.com/a/fUzFF

The cocktail:

Just a standard Old Fashioned

The foam:

4 egg whites

3 oz. lemon [he later suggests you use less lemon]

2 oz. simple syrup

1 oz. water

6 oz. of offgassed beer [he suggests stout, and later suggests more beer]

The procedure:

1. Add the foam ingredients to the whipper

2. Shake, add N2O, and let set for 1 minute. Add another N2O cartridge, shake for 1 minute.

3. Place in the refrigerator for 1 hour

4. Make the cocktail

5. In a chilled glass, ‘bottom’ the drink with the chilled foam.

6. Strain in the chilled drink.

NOTE: Kevin Liu recommends removing the lemon juice entirely, since the beer itself should have more than enough acidity to stabilize the foam. He recommends for pure beer foams 2xN2O and 1xCO2 cartridges.

Grand Marnier Cocktail Foam

(Kathy Casey, http://vimeo.com/channels/248411/34971663)

The cocktail:

Any. Suggests a Black and blue Cadillac Margarita.

The foam:

2 sheets gelatin

2 oz. fresh lemon juice

6 oz. simple syrup

4 oz. pasteurized egg whites [can be powdered, but not sure about the 4 oz. anymore]

3 oz. Grand Marnier

The procedure:

1. Bloom the gelatin sheets in ice water for 10 minutes

2. Combine lemon juice and simple syrup. Strain through a fine strainer into a saucepan.

3. Remove gelatin, squeeze out extra water and add to saucepan.

4. Heat over medium-high heat until gelatin just dissolves - immediately remove from heat. Do not let boil! Cool for 10 minutes on the counter.

5. Place egg whites in a bowl, then whisk in the cooled solution until incorporated.

6. Add to foam whipper and charge with 2 charges of N2O. Shake briefly in between charges.

7. Refrigerate for at least 4 hours, better if done overnight.

‘Guinness Foamed’ Beer:

(Kevin Liu, http://drinks.seriouseats.com/2013/07/cocktail-science-foam-eggwhite-gomme-dry-shake-beer-foam-eggwhite-alternatives.html)

drinks.seriouseats.com has a foam article that tells you to make any foam out of any beer with 1 or 2 charges of N2O and 1 charge of CO2 (with a ‘decarbonated’ beer). Interesting. The foam lasts for about 3 minutes and the foam started to melt away. A scant pinch of xanthan gum per 12 oz. of beer helps to stabilize the foam. The addition of the xanthan gum necessarily decarbonised the beer, therefore the CO2 charger is required to get a standard beer back out.

Experimental Design:

This lab examines the ingredients that go into a successful bear foam. We (myself and the friends and acquaintances I used as taste testers) define a successful beer foam as a foam, made primarily out of beer, that tastes like beer, that maintains a foam-like consistency for an appreciable amount of time, and is generally appetizing. We scoured the Internet for any recipe for a beer foam or cocktail foam (finding mostly cocktail foam recipes, and only one explicitly for a beer foam). These recipes included only a few necessary ingredients: beer, egg whites, and gelatin. Some had peripheral ingredients including simple syrup, water, lemon juice, and other gelling agents (including xantham gum and cellulose powder), but being a preliminary experiment we stuck with the basics. Our experimental procedure is outlined below:

1. 8 oz. beer plus 2 charges of N2O (hereafter called “simple”)

2. “simple” + 2 oz. egg whites

3. “simple” + 4 oz. egg whites

4. “simple” + 3 oz. egg whites + 1 sheet gelatin

5. “simple” + 3 oz. egg whites + 2 sheets gelatin

NOTE: The amount of beer is reduced by the amount of egg whites added to comply with the pressure whipper specifications (no more than 8 or 9 oz. of total liquid).

Methods/Procedure:

The procedure is simple, and is based primarily off of the Bourbon Barrel Foam Recipe of “TWDIndustries,” with the suggestion from Kevin Liu that lemon juice is not necessary since beer has enough acidity already. The procedure consists of:

1. Off gassing 6 - 8 oz. of your beer of choice (I chose Southern Tier 2XStout)

2. Adding the gelling/foaming ingredients. If gelatin is used, heat the beer so that the gelatin dissolves fully, then cool it to a temperature that will not cook the egg whites.

3. Add the beer solution to the Pressure Whipper, seal it, and add 2 charges of N2O gas (shaking briefly in between each addition).

4. Chill the Pressure Whipper for at least an hour, preferrably 4 hours (or even overnight).

5. Release, and record, the resultant beer foam.

6. Observe and record the general appearance (consistency, structure), observe how the beer foam collapses (do bubbles grow quickly? does the structure collapse in itself? how long does it take for ~ 2 cm of the original beer to form at the bottom of the glass), taste (does it still taste like beer? what is the mouthfeel? is is still appetizing?), and make general observations about the overall appeal of the resultant foam (i.e. will someone actually want to consume this? how long do they have before it collapses or becomes unappetizing?)

1. “simple”	Foam Lifetime: less than one minute Taste/Mouthfeel/Appeal: like regular beer What did it look like after it collapsed? like regular beer Overall rating/conclusion: really not a foam at all, just a vigorously shaken beer
2. “simple” + 2 oz. egg whites	Foam Lifetime: less than 5 minutes Taste/Mouthfeel/Appeal: very creamy initially What did it look like after it collapsed? rather gross, with networks of proteins Overall rating/conclusion: great for the first few minutes, then unappetizing
3. “simple” + 4 oz. egg whites	Foam Lifetime: around 5 minutes Taste/Mouthfeel/Appeal: not much different from the 2 oz. egg whites What did it look like after it collapsed? very similar to the 2 oz. egg white foam Overall rating/conclusion: don’t really need 4 oz. egg whites for this foam
4. “simple” + 3 oz. egg whites + 1 sheet gelatin + chilled for 2 hours	Foam Lifetime: almost 10 minutes before it started to really collapse Taste/Mouthfeel/Appeal: creamy, a little jello-like What did it look like after it collapsed? a little strange, it didn’t hold its structure very long Overall rating/conclusion: appealing and promising, if only it could last longer
5. “simple” + 3 oz. egg whites + 2 sheets gelatin	Foam Lifetime: nearly 20 minutes before significant collapse Taste/Mouthfeel/Appeal: very much like jello, intriguing! What did it look like after it collapsed? the foam collapsed in a weird way, looked a little like brians Overall rating/conclusion: best yet! perhaps add egg yolk as emulsifier? or use Agar Agar?

Discussion & Conclusions:

It is clear that the egg whites are essential for any successful beer or cocktail foam. The egg proteins provide the backbone of the foam structure, and although we didn’t try a pure beer/gelatin foam, we are fairly confident that this would not produce an appealing foam (perhaps a beer gelatin?). Adding some egg-yolk instead of just egg-white may serve as an emuslifier which could extend the life of the foam and/or improve or preserve its desirable texture. However, adding a whole egg to 8 oz. of beer is likely to significantly change the taste of the foam. This is ultimately undesirable.

In all cases in our experimentation the beer foam didn’t keep its most appealing structure (a nearly frozen yogurt appearance, creamy texture, and tiny, uniform bubbles) for more than 5 minutes. It would be really nice (perhaps revolutionary?) if we could get the foam to maintain the texture and structure of a whipped cream (i.e. 30 minutes or more of smooth and appealing texture and appearance). This would allow the beer foam to be used as more of a mousse-like dessert or dessert topping, or even some addition to other foods (i.e. an IPA dip for french fries? a brown ale foam to top a stew? chocolate cake with a chocolate stout foam topping? just think about the possibilities!).

Our next steps are going to be examining the possibilities of adding some fat to the solution to reach the minimum 30% fat content required to create a whipped cream foam-type product. Generally, beer is free of fat, so the introduction of fat to the solution is likely to change the taste of the product. But if we used a strong, chocolate stout and was able to mimic, or at least approach, a chocolate mousse, we might be able to make this work.

In the meantime, I’m likely to try other beer styles with the 3 oz. egg white + 1 sheet of gelatin recipe. A bartending acquaintance has strongly recommended the use of Agar Agar instead of gelatin. There’s also the xantham gum and cellulose powder possibilites from the Dark and Foamy recipe, although since they didn’t specify the amounts we will have to conduct further experiments if we go down this path.

First Impressions, My Experience with Scientific Publication, and a Summary of the Problem

I found out about this P2PU course from my brother. He is training to be a lawyer and is very interested in intellectual property rights and the digital world. When I published my first scientific publication in 2011, he asked me whether I own the copyright and had the right to freely distribute the paper as I wished. I said, honestly, "I don't know," and then, still honestly, "I don't think it matters. It's out there and the people that would desire to read it can easily get it." At the time, I had hardly thought about open-access (OA) journals and whether or not I should publish in them.

I'm getting ready to publish another large paper in a subscription journal, as this is still the norm among my advisors and peers, and within a year hope to get one or two additional smaller papers. I'm considering publishing these in OA journals.

So, from what I've read so far, here's the OA case in a nutshell: Traditionally (i.e. before computers/Internet) it was time-consuming and expensive to publish scientific results. Busy scientists didn't want to spend their time on the nitty-gritty of copy-editing, printing, and distribution, so publishers stepped in. These publishers established structure in which a scientific paper could be submitted, reviewed by (volunteer) peers of the scientist, and published. The publisher then sold the publication to other scientists or scientific institutions where the target audience could easily access it. The system was good, and it became the norm.

Now, with the power of the digital world and internet connectivity, much of the function which the publishers previously contributed to this process has changed. It's no longer expensive to distribute results. If I sent a copy of a paper I published to a colleague, or a thousand colleagues, my copy is not changed in the slightest. It's actually quite amazing. But the traditional publication system is relatively unchanged. So I use it, just like (nearly) every other scientist I know.

I get access to practically any scientific paper I desire because I work at a research institution which subscribes to all of the relevant journals that I care about. I can Google my name, find my publication, and as long as I'm on campus, I can download it for (from my point of view) free. I can email copies of a pdf version of my paper to whomever I chose, and because it's a fairly small set of people that would actually care to read my paper, I practically never have to worry about copyright or re-use rights. I'd like everyone to be able to find my paper from anywhere and use the results for better research or better understanding, but this problem doesn't impact my day-to-day life all that much. It floats around along with hundreds of other issues which I should probably pay more attention to and be more active in solving.

Additionally, there's a moral / fairness issue to consider. Since I'm funded by government money, ultimately paid for with everyone's tax dollars, my results should be made available for everyone to read if they wanted to. Currently, unless you have a (typically pricey) subscription to the journal, or access to a research institution and the library system managed by that institution, you cannot access my results for free. You would have to pay (quite a lot of money) out of your own pocket do download my article from your home computer. This is because the publishers typically own the copyright, and the re-use rights, of my  publication, which is silly, because they did the least amount of original work in the entire process. This does not seem to be a good system

So, to wrap it all up, OA is "free, immediate, online availability of research articles with full re-use rights [1]." The current problem is that "among the five value adders - authors, editors, referees, funders, and publishers - publishers add the least value and generally demand the ownership rights [2]". But this system is not set in stone. The system exists through tradition, but "there's no evidence that [the Scientific Publishing model we have now] is optimal. We need to experiment will all sorts of different Scientific Publishing Systems and...Openness is clearly the future [1]."

[1] http://www.youtube.com/watch?v=L5rVH1KGBCY
[2] http://legacy.earlham.edu/~peters/fos/overview.htm

P2PU: Open Science

This is a placeholder for my blog for the P2PU: "Welcome to Open Science: An Introduction".

Briefly, I'm a 6th year Ph.D. Student at Cornell University studying climate science and atmospheric chemistry. I've published a paper (and am currently submitting a second one) to non-open source journals, as this is the norm among my advisors and peers.

My first scientific publication!

Although this post will probably be quite boring to many, I thought it might be good to show the process by which a scientific paper gets published. While I cannot speak for all atmospheric and climate scientists, I can speak for me, and my story (hence "Climate Through Anecdote"). In my case, it took about two years to learn the model, run the experiments, and submit (2009 - 2011) and less than four months to go through the submittal, peer review, revision, and acceptance process (February 23rd - June 4th, 2011), and finally got published on September 15th. Overall, the submittal/revision/publication process went pretty quickly. So here we go:

0. Read grant or proposal, decide what you're going to do (2009)

1. Run experiments / run models / do science (2010)

These can be described briefly, as parts of them have been written up previously. After my first year of classes and some work on a biofuels project, I began to learn how to run the CCSM (Community Climate Systems Model), work through test runs, make modifications, check the chemistry, and do a lot of the science part of this project. There was no experimenting here. No data gathering. No lab equipment. Climate modeling, for the most part, uses existing models, plus new, creative modifications, or newer data from observations to simulate the global climate. I had both.

I (with tremendous guidance from my advicor) added some artificial tracers (basically, fake chemicals that had particular properties that would elucidate aspects of the model, and through that aspects of the real world) to track the chemistry, transport, and seasonality of Asian emissions as they moved from Asia, over the Pacific, and into the US. Once all of that was finished, and the data was produced, the next step was to...

2. Determine what is worth focusing on, writing, publishing, and exploring (2010)

3. Write it up (Intro/Methods/Results/Discussion/Conclusions) (2010-2011)

I spent about two semesters in this data analysis and write up stage. The two kind of blurred together, where I would average the emissions for the spring, summer, winter, and autumn at various layers in the modeled atmosphere, talk to my adviser, double check my work, document what I did, go back and change the code, or change the area, etc. All the while trying to both figure out and show what Asian emissions were doing over the Pacific. The modeled results showed a large and looming Asian Pollution Plume extending over the Pacific, and over North America during certain seasons.

After many months, I had a set of figures that I thought showed the most interesting aspects of the Asian Plume, and I started to craft them into a story. At the same time, I reviewed all of the relevant literature again, and produced a draft of my paper. Abstract - Intro - Methods - Results - Discussion/Conclusions - References. I gave these to my adviser, and thus we began to...

4. Edit, edit, edit, edit, edit, edit, edit, edit, edit until you and your adviser are satisfied (2011)

This was a frustrating process. I had to juggle all the possible figures, the possible ways of explaining what was happening, the available and relevant literature, the revisions my adviser handed down to me, the changes I wanted and did not want to make, as well as classes and my non-academic life. I usually felt good about a draft I handed in, and when it came back all splotched with red ink, I would feel a little hurt and deflated. I would then read the revisions, reformat, reorder, redo figures, look up new papers and studies, and get another draft. Each time, the paper got better. The story and message solidified. Three or four major figures became the centerpiece of my research. By the time February 2011 came around, I was ready to...

5. Submit (2/23/2011)

We chose the Journal of Geophysical Research - Atmospheres (http://www.agu.org/journals/jd/) to submit to, as this is where a majority of the papers I had read came from, and is more or less the predominant atmospheric and earth science journal out there. The submittal process was tedious. Everything had to be formatted and pieced together just right. The figures had to follow certain rules. I had to merge everything into one big pdf file, as well as individual figures and sections. This took a week or so, and I managed to submit the day before my 25th birthday. Next, I had to...

6. Wait, and do other work

At this point, I had a lot of class assignments to work on, so I more or less forgot about the paper. It often takes several months before you hear back, and so I thought it best just to forget it ever happened. I figured I'd hear back in June or July, and until then I would focus on my classes and future projects. Instead, I got an email within five weeks of my submittal, with the words...

7. Accepted with Substantial Revisions (4/4/2011)

Dear Dr. Brown-Steiner:

Thank you for submitting "Asian influence on surface ozone in the United States: a comparison of regional chemistry, seasonality, and transport mechanisms" to Journal of Geophysical Research - Atmospheres. I have now received 3 reviews of your manuscript, which are attached for your reference, as well as a brief evaluation by an Associate Editor. Based on the review comments, I find that your manuscript may be suitable for publication after substantial revisions.

Wow! Accepted! So soon? And why do they think I'm a doctor? The editor was brief in his comments:

Please address the comments made by the reviewers. Especially address the comments made by Reviewer #2 as to model validation and verification. Please submit your revised manuscript by May 18, 2011.

So my new task was to address every comment made by the three reviewers, in just over a month. So I began to...

8. Address Comments and Substantially Revise (April-May 2011)

Some of the comments were harsh. Others were uplifting. I'll include some of them here, for flavor.

The first reviewer:

This manuscript takes a new and effective approach for quantifying the impact of Asian emissions on US surface ozone. I especially like the breakdown of Asian ozone into baseline, seasonal and chemistry components, as well as the analysis of transport to the surface via the dry airstreams of mid-latitude cyclones. I think the paper will make an important contribution to the scientific literature and I expect that it will eventually be published in JGR. But first the authors need to conduct a borderline major revision to add further discussion on mechanisms that bring ozone to the surface, correct many citation errors and to improve the overall style of the paper.

The third reviewer:

The authors use a 5-year simulation from a chemical transport model (CAM-Chem) to study the influence of Asian emissions on surface ozone over the United States, with a focus on the western and central United States. The study design creatively allows for a clean separation of the role of seasonal changes in transport pathways, seasonal changes in the Asian pollution source, and seasonal changes in chemical evolution of Asian plumes transported into the atmosphere over the United States. The study is suitable for publication inJGR, following the suggested revisions below, which are mainly points of clarification.

And the second reviewer (the "Reviewer #2 mentioned by the editor, so I saved this one for last):

This paper presents a new analysis using the CCSM-CAM global model. As a conceptual analysis, this paper succeeds to present a useful framework for the processes involved in long range transport of ozone. However as a quantitative analysis, it fails due to its lack of any serious evaluation of the model results against observations...While no one expects any model to be perfect, we do expect a serious evaluation of the results against observations and a discussion of how these biases impact the results. The authors have failed to do this. For this reason, the paper should be rejected. The authors need to go beyond the HTAP evaluation and do a better job at evaluating their model results. Insight into the cause of any bias can be examining how the model behaves seasonally, at altitude etc. Assuming the authors wish to redo this analysis then I offer the following additional comments for them to consider...

The first and third reviewer had plenty of minor and moderate comments, specified by the lines in the manuscript, which looked like this:

L35-39. Quantify the increases over some time period. The Cooper et al. 2010 study focused on the free troposphere (not surface) . The HTAP studies, referenced later, also address this point; see Reidmiller et al., ACP, 2009.

L77-78 State that this refers to Asian component only (also L225, L272)

L 111-115 The specific definition of anthropogenic xNOx should be included - biomass burning? Fertilizer? Soil NO? Is there seasonality in the xNOx emissions or does the "seasonality" tracer introduced later solely reflect seasonality in venting of the Asian boundary layer + transport pathways?

L129-133. It's clear later in the text, but best to explain here why the scaling is necessary and also what is meant by "seasonality and chemistry signals".

I was a little sloppy with my citations, and checking my numbers precisely. I am thankful, and startled, at the level of detail that these reviews analyzed and critiqued my paper. The first and third reviewers' comments were fairly straightforward, and very detailed. The second reviewer’s comments were more vague, more substantial, and required a lot more work. Essentially, I created a whole section of supplementary material, that would be available online and not in the actual paper, that compared the model results to known and measured observations all over the US. This included seasonal averages and variations, day/night cycles, and others. It was tedious, and often felt a little pointless. I was rushing through this analysis to get the paper back by the deadline, and others have, and would in the future, do a much better job of this validation and verification of the model I was using. However, it was an actual check of my model output with the real world, so I added the supplemental material, finished the revisions, added the new figures, and proceeded to...

9. Resubmit and Wait (5/18/2011)

Once again, now I tried to forget about the paper. I was thrilled, because it was accepted. But I was worried that they wouldn't approve of my revisions, or want more verification. In less than a month, however, they got back to me, and...

10. Acceptance! (June 13, 2011)

I am pleased to accept "Asian influence on surface ozone in the United States: a comparison of chemistry, seasonality, and transport mechanisms" for publication in Journal of Geophysical Research - Atmospheres.

I was in! It would be published! All that was left was copy editing, some final revisions, color changes, and brief communications with the copy editor, and I would be published. I began to interact with the journal throughout the...

11. Copy Edit

I got various emails with revisions, citation questions, and author queries throughout the summer, and on August 24, 2011 I received my final proof to read through in two days, where I would be...

12. Published (September 15, 2011)!

The wait for final publication took longer than I expected. But finally, after three years, I had my name as the primary author on a scientific publication! You can see the abstract and front material here. And here is a screenshot of it appearing on the "Just Published" tab of the JGR homepage. I could talk a lot more about the peer review process and the research, but I’ve gone on for too long already. Thanks for reading!

Communication . . . I need to do more of it

Randy Olson is coming to Cornell to give a quick workshop on Science Communication. He has a recent book out called "Don't Be Such a Scientist," which I grabbed at the library last week, not knowing he was coming. He also has a movie called "Sizzle: A Global Warming Comedy" which is playing at Cornell Cinema during his time here.

So all of this has resparked my desire to simply write about my work. Make it exiting, if it is (which it's often not), but mostly to be honest, transparent, truthful, and clear. I'm shooting for weekly updates, starting now. So if you're reading this, and I slack off, hold me to it! Scold me!

This week, I'm returning to campus after a hectic summer. I have stacks of daunting, not terribly exiting work ahead of me. More modifications of emissions files. More nitty-gritty fighting with the climate model. A TA-ship, where I'll grade homeworks, and teach a class or two. On top of all that, I'm taking a two-semester sequence of classes called "Mathematical Physics" to give me the tools I need to know what I'm doing.

On top of all that, I have a new house, four new housemates, many beers, ciders, and meads to brew, and a new park in my backyard to explore. Here we go!

When does it get personal?

The impacts of climate change are very often described and thought about in the abstract, especially if you live in a place where there are little or no actual impacts. Statements like "Expect sea levels to rise by 0.5 to 1.0 meters by 2100" or "Expect 5 more extreme heat and smog events every summer by 2050" don't necessarily carry a whole lot of weight. Could a 2 degree Celsius change really impact my life all that much? These projections and estimations, ripe with uncertainty and ranges and controversy, are hard to discern, and hard to feel. They don't touch us. We don't feel it, and therefore tend to ignore it to wait and see.

That urge to wait and see, that abstraction, starts to fade when you can feel it personally. This spring, Lake Champlain (located between New York and Vermont, near Canada), where my family owns a small cottage with about 100 feet of lake front, has had the highest water level since the records started. Below is the 2010 lake level, with the bold red being the maximum level ever observed. You can see during April and May, the lake level has never exceeded 102 feet.

The next graph is the lake level so far for this year, and you can see that the late-April and May period has been record-breaking, by about one foot. In Early May, the lake level exceeded 103 feet for the first time ever.

What does a foot of extra water look like? How much does it impact a shoreline? First, a picture of our shoreline from 2004. Note the tree behind Sam (in the orange hoodie).

Here's a picture taken during a particularly windy day early this May. Note the tree, the same tree that was behind Sam earlier. Also note the water making contact with our little boat house.

Here's a picture from 2002 looking out at the lake. Note the tree (a different tree than before) and a stump just beyond the rock-wall of our shore.

Here's a picture from last weekend. You can see the tree next to my Dad and a friend, and the stump out in the water.

The rock wall has been demolished, and you can see significant erosion, with exposed roots and dirt.

The records of lake level started in the 1800s, so let's say that they've been kept for 200 years. A lake level like this, then, could be considered a 200-year event, and we would expect it to come once every five-generations or so. That "200-year event" phrase is slippery, since we only have one data point. But as my family plans and figures out how to deal with our shoreline, we are trying to determine if we should plan for another 200-year event.

And since there is so much data, and publicity, and controversy regarding global warming, the topic has been brought up. Should we build a wall? How big do we need it to be? What lake level should we plan for? Is this related to global warming, or is it just an extremely unusual year? We're wondering if this 200-year event might become a 100-year event.

And since we don't really know what to expect in the next 100 years, because the planet is changing in observable and predictable ways, because Mother Nature is no longer regular and our historical records no longer hold the same weight that they once did, every new strong storm, extreme weather event, and record lake level has shifted in meaning slightly.

(The same can be said for families struck by the record-setting tornadoes this April, families impacted by Katrina, families impacted by the extreme drought in Australia, families worried about freshwater coming from the Colorado River, or heat-waves in Chicago, and the people living on the drowning island of Tuvalu.)

All of these events, which would be devastating during any era, are no longer necessarily Acts of God, or the regular cycle of Mother Nature. They all now all have a slight tinge of: "Is this something we're doing? Is this partly our fault?" We are having a harder time making decisions, because we can no longer confidently look into the past to get an idea of what the future might bring. And that makes it much more personal.