yeast – Page 2 – The Big Room (and the little things in it)

I finally got to Bristol Brewing Company…

Signage in front of the Bristol Brewing Company After spotting the company’s mention in Jeff Sparrow’s “Wildbrews“, I’ve been wanting to visit Bristol Brewing Company, particularly since they may be the only such brewery using local yeasts and bacteria that they isolated themselves from their local environment.

Since we’re moving from Southeastern Idaho to Southeastern Texas, I’ve been going back and forth between the two location. It just so happens that along with New Belgium Brewing Company, Bristol Brewing is actually right along a convenient route between the two locations. (Let’s see if I can figure out how to work the Google Maps plugin):

How’s that look? How does it work? (Those of you reading this on the RSS feed: The interactive map only appears on the website, it would seem. Please check it out here.) I made the KML file myself…

Bristol Brewing is a cozy little brewpub, and the people there are encouragingly helpful. They were in the middle of bottling, so there were no tours. Also, there were not currently any of the skull-‘n-bones beers available. However, I did get an educational series of tastes of their current brews on tap (thank you to the employee I spent most of the time talking to whose name I’ve embarrassingly forgotten, but who I believe was Tad Davis judging from the photos on the web site). I also lucked out and their microbiologist, Ken Andrews, happened to be there. I asked about their native Colorado brewing flora. Turns out Bristol Brewing isn’t quite as bold as I originally thought. They’re still doing their primary fermentation with “normal” brewing yeasts. What they’ve done is inoculated some wine barrels with the locally-isolated yeasts and bacteria, and they use the barrels for a secondary fermentation and aging instead. Much safer if you have to worry about having a drinkable product at the end, and of course it makes me feel like more of a crazed rebel for wanting to isolate my own local bugs for the main fermentation. So, a great visit overall.

Incidentally, it seems they’ll be tapping a new Skull-‘n-Bones brew in a couple of weeks, at 5pm on Tuesday, May 27th (2008). It sounds like they’ll probably have some available for a few days before it all disappears, so I’m hoping my return to Texas can be timed such that I can swing by and at least get a taste.

Boosting fermentation with science

All right then – I’ve got five pounds of honey, a pound of frozen cherries, packets of a couple of different dried yeasts, miscellaneous other potential additives, two 2-gallon polyethylene terphthalate fermentation containers with screw-top lids and spigots, several feet of aquarium airline tubing and connectors, silicone sealant, and miscellaneous kitchen gadgets (including a hydrometer). Now it’s time to discuss what I’m about to do and fish for comments and criticisms before I jump into it.

My goal here with this brewing experiment is a quick primary fermentation. And to compare the results from two different yeast strains, uh, TWO goals, quick fermentation, yeast strain comparison, and fermentation container design. THREE goals. Quick fermentation, comparing yeast strains, fermentation container design, and to try to keep the yeast cultures from dying off too quickly during the fermentation. FOUR. Four goals…

In this post, I’ll stick to talking about what I’m putting into the brew and how I hypothesize my additives and process with speed the fermentation along and help keep a large portion of the yeast viable during the primary fermentation.

Actually, the health of the yeast populations and the speed of fermentation are overlapping goals; more cells remaining alive and healthy means more cells simultaneously chewing up sugars and spitting out ethanol for me, resulting (hypothetically) in faster primary fermentation. In this experiment, I’m going to be focussing on nutrients and spices that are reported to benefit yeast activity. Here’s the process I am currently planning to follow, focussing primarily on the fermentation-boosting parts:

I’ll boil the 5 pounds of honey with enough tap-water to make about 2 gallons of must, adding the frozen cherries sometime after the boil gets underway.

Fermentation boost: we have water so hard that you have to wear a helmet to take a shower. (Joke stolen from my Environnmental Chemistry instructor, so you can blame Dr. Rosentreter for that one). It’s loaded with Mg²⁺ and Ca²⁺, which seem to be able to help the yeast to produce ethanol faster and survive higher ethanol concentrations better[1][2] as well as just being general nutrients[4].

Two approximately �-liter amounts of the must will be put into clean glass quart bottles and used to develop the initial yeast culture for pitching (each one for a different strain of yeast).

Fermentation Boost: Growing up a large population of yeast from the dried yeast packets before pitching will give me a faster start. In addition, the large headspace and the use of cloth rather than plastic or rubber covering of the top will allow oxygen to get into the starter culture, helping it to develop more quickly and in a more healthy fashion (i.e. a larger proportion of healthy, viable cells).

Nitrogen supplementation: Capsules of arginine picked up cheap at a certain big-box store will be added to the yeast starter.

Fermentation Boost: “Free Amino Nitrogen” is perhaps the most important bulk nutrient for yeast, and arginine seems to be the preferred amino acid source[3][4], presumably because it contains the most reduced nitrogen per molecule of the amino acids. I actually want to try to develop a process for using dry milk powder instead, but achieving sufficient hydrolysis of the milk proteins looks like it’s going to take some development on my part. For now I’ll “cheat” and use arginine instead.

Vitamin supplementation: A single well-crushed children’s “chewable vitamin” (“Flintstones�” or generic equivalent) will be added to each starter culture as well.

Fermentation Boost: Pantothenic Acid (Vitamin B5), Inositol, trace minerals, and small amounts of additional potassium and phosphate to supply vital nutrients to the yeast culture.[4]

Fermentation-enhancing spices: I will be adding ground ginger and cinnamon (actually cassia) to the must near the end of the boil.

Fermentation Boost: In addition to providing what I think will be excellent complementary flavors to the final product, it appears that even fairly large amounts of these two spices – among others – provide a boost to fermentation rate[5] (via Shirley O. Corriher’s “Cookwise”[6]) of Saccharomyces cerevisiae cultures. If I’m doing the conversions appropriately, the peak fermentation boost for ginger works out to something like 3 tbsp of ground ginger per liter, or something like (very roughly) 10 tablespoons per gallon. I don’t plan to add quite so much, but a couple of tablespoons of each spice in the two-gallon batch ought to provide some nice flavor while still hopefully providing a boost to the fermentation rate as well.

“Cinnamon”: In the US, the rust-colored stuff labelled “Cinnamon” is not, actually, cinnamon. True cinnamon (Cinnamomum zeylanicum)is actually tan in color. What you get in the US when you buy a bottle of “Ground Cinnamon” actually comes from Cassia (Cinnamomum aromaticum), a closely related plant. Realistically, as far as I have been able to find out so far, there’s not likely to be a huge difference in the active components or flavor. While I haven’t yet gotten my hands on a copy of the old article from Cereal Chemistry[5] mentioned above, I’d give good odds that the “cinnamon” used in the study was also actually cassia anyway.

There’s one more thing that I hypothesize would help promote my goals that could be added: small amounts of oxygen[7] (say, less than 13% O₂, or very roughly speaking, around half of the normal atmospheric concentration or less). However, I’m still trying to work out an easy way to achieve this automatically and am not yet ready to try it. Besides, this is already pretty poorly-designed for a “real” scientific experiment as it is, considering the number of variables that are really contained in this brewing process. Really, my hypothesis here boils down to a relatively vague “This mixture and process will allow me to finish the primary fermentation within a day or two of pitching”. If I ever have opportunity to do serious experimentation on this, it’ll require setting up a large number of separate fermentation reactions to assess the effects varying each individual set of hypothetically-fermentation-boosting additives. Hopefully one of these days things will settle down enough to let me try it.

If anybody sees anything stupid (or just interesting) up there, please say something…

[1] Dombek KM, Ingram LO: “Magnesium limitation and its role in apparent toxicity of ethanol during yeast fermentation.”; Appl Environ Microbiol. 1986 Nov;52(5):975-81.
[2] Nabais RC, S�-Correia I, Viegas CA, Novais JM: “Influence of Calcium Ion on Ethanol Tolerance of Saccharomyces bayanus and Alcoholic Fermentation by Yeasts.”; Appl Environ Microbiol. 1988 Oct;54(10):2439-2446.
[3] Carter BL, Halvorson HO: “Periodic changes in rate of amino acid uptake during yeast cell cycle.”; J Cell Biol. 1973 Aug;58(2):401-9.
[4] Fugelsang KC, Edwards CG: “Wine Microbiology – Practical Applications and Procedures (2nd Ed.)”; 2007; Springer Science+Business Media LLC; pp 15-18
[5] Wright WJ, Bice CW, Fogelberg JM: “The Effect of Spices on Yeast Fermentation.”; Cereal Chemistry. 1954 Mar;Vol.31,100-112
[6] Corriher, SO: “Cookwise”; 1997; HarperCollins Publishers, inc; New York; pp 69-70
[7] Nagodawithana TW, Castellano C, Steinkraus KH: “Effect of dissolved oxygen, temperature, initial cell count, and sugar concentration on the viability of Saccharomyces cerevisiae in rapid fermentations.”; Appl Microbiol. 1974 Sep;28(3):383-91.

Off-Topic and Back Again: “Framing”, Cluetrain Manifesto, and Twitter

“Framing” came up briefly on one of the other small independent blogs I follow. I’d link
to the post but it’s gone now. I sincerely hope its disappearance wasn’t related to the
comment I posted there, unless it was just because of the “don’t feed the trolls” part
of it – (in which case excuse me for a moment while I tell myself what an amazing fountain of useful advice I am and feel self-important for about 15 seconds before I return to reality…). I’m guessing the poster just decided he didn’t want to keep the post, but I won’t let that spoil my brief ego-feeding fantasy.

For those lucky enough to have missed it so far, here’s my flippant and extremely brief explanation
of my understanding of how the “framing” thing goes. An assistant professor of communications popped up among the science blogs one day with what seemed to begin as a couple of reminders of the obvious (mainly because it occasionally seems that people have forgotten). Namely, that if you want someone to understand what you are trying to communicate (particularly scientific matters) and agree with you, you are more likely to succeed if you can connect what you are discussing to something that your audience already cares about, and you are less likely to succeed if you are, shall we say, unfriendly to them as you present your subject.

From there, “framing” seems to have grown into something resembling the brand-name of some kind of mass-market “self-help” product line. Its primary proponent, from the distant vantage point
whence I occasionally catch a glimpse of the fight, starts to seem like the angry Vice President
of Communications for Science, Incorporated, whose office issues angry memos denouncing the insubordinate “screechy monkeys” who insist on deviating from the approved language when discussing Science, inc.’s Mission Statement. The fact that science is a conversation among people rather than a corporation probably explains why so much of the response has been not “Oh, crap, we’d better behave ourselves or we’ll get in trouble” but “Who the heck are you, and why are you telling me what I can say and how I can say it?” And that, I think, is all that needs to be said. (Anyone who stumbles upon my little blog and disagrees is welcome to say so in the comments.)

Actually, it’s probably more than needs to be said, and I wouldn’t have even mentioned it except that the problem of trying to apply this sort of approved “Command and Control” approach towards information in the Internet age reminded me of something else. The Cluetrain Manifesto was published so long ago that AOL was still considered a successful and valuable operation at the time, but it still seems to be relevant. (It’s free to read online – follow the link if you want to do so). At its core, its central thesis seems to be that the “Command and Control” approach to information management favored by corporate and political entities is effectively broken now because of the two-way communication made possible by a ubiquitous internet. In essence, “the market” is no longer made of isolated individuals passively sitting on the couch “consuming” the approved messages coming through the television, but a “conversation” of people who can easily tell the difference between a corporate “message” and authentic human conversation. Here’s a relevant passage:

“Imagine for a moment: millions of people sitting in their shuttered homes at night, bathed in that ghostly blue television aura. They’re passive, yeah, but more than that: they’re isolated from each other.

Now imagine another magic wire strung from house to house, hooking all these poor bastards up. They’re still watching the same old crap. Then, during the touching love scene, some joker lobs an off-color aside � and everybody hears it. Whoa! What was that? People are rolling on the floor laughing. And it begins to happen so often, it gets abbreviated: ROTFL. The audience is suddenly connected to itself.

What was once The Show, the hypnotic focus and tee-vee advertising carrier wave, becomes in the context of the Internet a sort of reverse new-media McGuffin � an excuse to get together rather than an excuse not to. Think of Joel and the ‘bots on Mystery Science Theater 3000. The point is not to watch the film, but to outdo each other making fun of it.”

And now we take one more step towards on-topicness: One current set of the metaphorical wires described in that passage is Twitter. Twitter is kind of like a gigantic lobby at a convention center where some huge conference is going on. The lobby is filled with little groups of people, collectively discussing with each other all kinds of little thoughts, observations, and events that each person there has encountered. You can easily wander through the lobby for hours, listening for snippets of conversation that relate to your own interests. Sure, being a raw, natural, human group of discussions, Sturgeon’s Law (“90% of Everything is Crap”) is in full effect. Sometimes literally: On Twitter I’m tracking the term “brewing” which seems to pick up more metaphorical uses of the word than literal, and a recent “Tweet” that popped up was somebody commenting that someone didn’t flush the toilet (“someone’s been brewing up a 1.6 gallon pot of turd stew.”)

So why bother? Because I think the remaining 10% has enough potential value to make a little mental effort to sift through the stream of messages worthwhile. I’d say a majority of the messages that come through are related to events happening at that moment. Twitter seems to get a lot of use as a back-channel for commenting on things that are happening, and for organizing impromptu gatherings. In most of these cases I think location information would be a valuable addition…and now I’m finally back to “on-topic”.

I think it’d be exceedingly nifty to be able to map Twitter messages in real-time. If I can convince anyone else that my “geostrings” idea is worth using, and then if one were to track “geostr”, any “tweet” with parseable location information would automatically show up. A small tag containing precise location information would make it possible for your computer automatically alert you if a post was describing something anywhere near where you are. Imagine the case of posts like “I just saw a tornado touch down, I’m going down to the basement now”. Or, say, “Who wants to try the homebrew I’m about to bottle?”

Example code in Javascript and PHP for picking out and parsing geostrings to follow soon. I’ll get back to yeast again shortly thereafter, though.

The care and feeding of Saccharomyces

Let me pause now for a moment to review what I’ve learned so far:

Yeast are filthy little jerks

No, seriously. I’ve previously reviewed their promiscuous sex lives,
their sexually-transmitted diseases, and their toiletry habits. Somehow, though I still want to do more brewing, so let’s continue.

Bag of 'Parodina Yeast Chow'. I am not affiliated with Purina Mills corporation! This image is PARODY!

Yeast need to be fed particular sugars

The three major elements needed by pretty much every living thing for “food” are Carbon, Nitrogen (as reduced “amino” nitrogen), and phosphorus (as oxidized phosphate) (Reduced sulfur is also needed in small amounts for proteins). Glucose (“dextrose” or “corn sugar”), fructose, or sucrose (“table sugar”, each molecule of which is made of a molecule of glucose attached to a molecule of fructose) are all used as carbon sources by Saccharomyces yeasts. Possibly also Galactose under certain conditions[1]. Saccharomyces yeasts don’t appear to be able to use lactose (“milk sugar”, each molecule of which is made of a molecule of glucose and a molecule of galactose), so some recipes include lactose in order to ensure there is some residual “sugar” in the mix at the end, for flavor and “body”.

Yeast need reduced nitrogen (amino nitrogen or ammonia…or urea)

Aside from sugars, this seems to be possibly the most important yeast nutrient. The most
“natural” source of this nutrient would seem to be amino acids or very short peptides (2-5 amino acids long). Apparently urea (carbamide) also makes a good yeast nutrient, but:

You don’t want TOO much nitrogen available to the yeast, or there’ll be excess urea dumped back into the brew

This could combine with the ethanol to make “ethyl carbamate”, which is considered
a probable carcinogen, at least if it’s present at a high enough level. Obviously if you use urea as a
yeast nutrient, that’s only going to increase the possibility of a problem.

Saccharomyces yeasts are effectively incapable of using proteins for nutrition.

Proteins can be a source of amino nitrogen (and carbon and sulfur), but like all real microbes, yeast cells cannot just “eat” chunks of protein. They have to be broken down into very small chains of amino acids or even as individual amino acid molecules before the yeast can suck them up and use them. Saccharomyces yeasts do not appear to normally excrete protein-digesting enzymes, so by themselves they cannot make any use of protein for nutrition[3].

Yeast need oxygen

Oxygen is necessary for making certain components of the cell membrane, in addition to it’s more obvious role in respiration. Without a way to replace used up membrane components, the yeast stop reproducing and eventually fall apart and die. There seems to be some suggestion that to a certain extent one can substitute some raw membrane material for oxygen here (either as “yeast hulls” or possibly even certain of the natural waxes on some fruits).

If you give yeast oxygen, though, they consume the sugars entirely instead of making alcohol…

…or do they? Between the “Crabtree effect” (when there are high concentrations of glucose, alcohol production continues even in the presence of oxygen) and indications in scientific papers[2], it seems SMALL amounts of oxygen may not be a problem, and might very well be beneficial.

Yeast need vitamins and minerals

B1 (“Thiamine”) is commonly mentioned, though apparently the need for it varies from strain to strain. Also potentially important are Pantothenic Acid (B5), Niacin (Nicotinic Acid, Vitamin B3), Biotin, Inositol, as well as Potassium, Magnesium, and trace amounts of calcium and a few other minerals[4].

Unhealthy yeasts are more prone to make (EEK!) Off-Flavors and Off-Odors (EEK again!)

For one thing, it seems to be a general rule that you don’t want your brew sitting on the corpses of dead yeast (the “lees” of wine, or “trub” of beer), because that is a potential source of (insert dramatic music and crash of thunder here)Off-Flavors and Off-Odors. Yeast dying and falling apart is also a major source of urea being dumped into the brew, too. Some strains of yeast under certain conditions, such as insufficient pantothenic acid, may be prone to producing nasty-smelling sulfides as well.

So, in most cases what we want to do when brewing is keep our yeast as alive and happy as possible, and get them to hurry up and finish our primary fermentation before they start dying off. Coming up: My (as yet untested) plot for accomplishing this – without specialized scientific equipment or materials.

[1] Wilkinson JF: “The pathway of adaptive fermentation of galactose by yeast” Biochem J. 1949; 44(4): 460�467
[2] Nagodawithana TW, Castellano C, Steinkraus KH: “Effect of dissolved oxygen, temperature, initial cell count, and sugar concentration on the viability of Saccharomyces cerevisiae in rapid fermentations.” Appl Microbiol. 1974 Sep;28(3):383-91.
[3] Bilinski CA, Russell I, Stewart GG: “Applicability of Yeast Extracellular Proteinases in Brewing: Physiological and Biochemical Aspects.” Appl Environ Microbiol. 1987 Mar;53(3):495-499.
[4] Fugelsang KG, Edwards CG: “Wine Microbiology: Practical Applications and Procedures” 2007; Springer Science+Business Media LLC, New York; pg 17

What really counts as a “microbe”?

Just a brief pre-post before the main one I’ve got brewing now (which will be posted either later today or tomorrow).

A tapeworm: Since when does 30-36 feet long count as 'micro'??? Microbiology is the dominating topic of this particular blog, but I don’t think I’ve ever addressed what I consider to really count as “micro”biology. This isn’t necessarily an obvious topic. My old “Microbiology” book from 8 years ago, plus the textbook from last year’s “Pathogenic Microbiology” class both contained large sections discussing organisms that are visible without a microscope. Heck, the “Pathogenic Microbiology” text even had a whole section on spider and insect bites. And, tapeworms? Since when is “over 30 feet long” considered “micro”? As I like to say: It’s time for Microbiology to grow up and move out of Medicine’s basement.

So: Here are the defining features of what I consider to be a “microbe”, at least for purposes of what I tend to discuss here on the blog:

Obvious: the organism cannot be effectively examined visually without a microscope and individual organisms can virtually never be observed by the “naked eye”.
In nature, a full normal population of a microbe can and will develop from a single live cell, and isolated individual cells are reasonably commonly observed.
Microbes do not “eat”.

It’s that last point that prompted me to write this post, mainly because it’s such an important part of why microbes work and how they affect their surroundings, especially when it comes to food microbes. What I mean by “do not eat” is that they are incapable of taking large (microbially speaking) chunks of material into themselves to use. Any cell nutrient for a microbe must be in the form of small molecules, like sugars, small peptides or individual amino acids, and so on that can be easily transported across the cell membranes and through the cell wall where applicable.

The importance of this is that for a microbe to grow on a complicated substance like meat or bread (for example), they have to excrete specialized enzymes that break down the substances out in the environment into simpler components like sugars or small peptides. If a microbe cannot secrete a protein-digesting “protease” enzyme, it can be surrounded by tasty, nutritious proteins and still starve to death. If a microbe can’t secrete an amylase (starch-digesting) enzyme, it doesn’t matter that starch is made of nice yummy glucose molecules because they’re all wadded up into long chains of starch that the microbe can’t get at.

And that, finally, is important because it brings up issues of growing multiple microbes together to accomplish something. Sake, for example, is made by fermenting rice, but rice is made primarily of starch. Saccharomyces yeasts don’t make amylases, so in order to make sake, you also have to add a kind of mold (Aspergillus oryzae, one of the types of white-mold-with-little-black-specks that you may see growing on the bread you’ve left sitting around for too long). A. oryzae is also a microbe and therefore can’t “eat”, but it does produce amylase. Since the amylase is breaking down the starches outside of the cells, this means the released glucose is also available for the yeast to use.

Admittedly, my definition above isn’t perfect. On the one hand, it leaves out protozoa (like amoebae and the well-known Paramecium, both of which actually do take in “chunks” of food, but both of which most people would normally consider to be “microbes”. It also leaves IN things like mushrooms, which are not usually thought of as being “microbes” by people who aren’t microbiologists. And, of course, it leaves me with no excuse not to go and learn something about eukaryotic (“plant”) algae (as opposed to bacteria-algae, a.k.a. cyanobacteria) and diatoms. Suggestions for updating my definition may be left in the comments…

Just something that came up while I was assembling what will be the next post. Stay tuned.

Do Not Want: Celestron LDM

Back in Idaho for the moment. The trip was somewhat exhausting, but I thought a followup to The previous post on the Celestron LDM microscope was in order, as I finally got a reply back after almost two weeks.

(20080329:Quick update. I am surprised to see this post is getting more interest that I’d anticipated. I’ve added a brief summary to the end of the post to help clarify my opinion since it seems people may be interested.)

I had asked them if it was possible to replace the objective lenses (so as to be able to use an oil-immersion lens to get 1000X magnification – pretty much a neccessity for decent bacteriological work – such as examining yogurt cultures) and whether the camera could be swapped for a regular eyepiece. Larger yeast cells used in brewing might be okay in 400X, but even there it’d be nice to be able to zoom in adequately to get better detail – like watching conjugation or budding of yeast cells.

The answer:

“The answer is ‘no’ to both because of the sizes, etc. are specific to this unit.”
Email ID: ZZR-372549
Department: Technical Support
Priority:
Status: Closed

I guess there’s no point in asking about getting a darkfield condenser for it. On the plus side, they did actually give me a reply at least.

I’ve got to say I’m seriously disappointed that Celestron has evidently intentionally engineered this microscope product (and their other offerings as well, perhaps?) to Not Play Well With Others. Why else go to the trouble and additional expense of coming up with your own special specifications for the parts when standard parts are readily available?

This seems especially absurd in a product aimed at science enthusiasts, who strike me as very likely to be strongly aligned with the “Maker” attitude…at least if they’re any good at Science Enthusiasm. I think the “if you can’t open it, you don’t own it” concept meshes very well with the investigative attitude necessary for science. So, we want “internet”, and they give us “AOL” instead. A sad, sad fate for an otherwise great concept, and on this basis I must render a verdict of “Do Not Want”.

Find me a version of this product – from any vendor – which can accept standard oculars and objective lenses and I’ll sell blood plasma and beg on the street to raise money for it. (If nothing else, it’d give me an excuse to finally start up the “science begging” blog-post series I’ve been threatening for a while now…) Of course, it’d be nice to have an ordinary “real” microscope, too…this blog still doesn’t have enough pictures.
(P.S. Dear Celestron: although I doubt anybody at Celestron will ever even see my obscure blog, and in that respect my previous post’s comment about sending me one to review was just a joke. Despite this, I was sincere, so in the unlikely event that someone out there sees this post and has the authority and inclination to do so, feel free to send me one to review anyway. And a pony.)

SUMMARY (in my opinion):
Good:

VERY nice, highly desirable concept overall.
Self-contained, platform-neutral design, should work with anything that can support SD cards or USB Storage devices.
Potentially a nice field microscope? (Probably not hard to hack together a battery pack that could be used in place of the AC adapter)

Bad:

Does NOT appear suitable for bacteriological or similarly high-magnification applications
Non-standard components prevent upgrades.
Non-standard components mean vendor lock-in problems (if Celestron gets tired of making replacement parts and some kid scratches your objective lenses or cracks the viewscreen, you’re out of luck.)
Digital camera and viewscreen appear to be integral, so if the camera or viewscreen dies I’d guess the whole device becomes a useless lump.

My recommendations for Celestron or other microscope manufacturers (should any of them care about the opinion of some nerd on some obscure blog like this one):

Please, please use standard parts wherever possible – it makes your device a much safer bet for anyone thinking ahead towards possible upgrades or replacement parts.
Don’t ignore bacteriological applications.
Easily replaceable parts make for graceful failures. For example, if the camera on this model could be swapped for an ordinary ocular, the microscope would at least be usable while the camera portion was being sent in for repair or replacement.

More on the shocking life of yeasts

(Brief Update: Hello Ontario! Did I attract the attention of a Toronto homebrewing club or something? Anyway – welcome!)

I am amazed at how much depravity I uncover as I explore the mystery that is
Saccharomyces cerevisiae.

I’ve previously discussed how the filthy little beasts have drunken orgies and exchange sexually transmitted diseases with each other. Now I find out the inebriated little jerks are peeing in my beer, possibly to try to give me cancer!

No, seriously. Given enough “Free Amino Nitrogen”, for example in the form of the pirate’s favorite amino acid, like tiny little single-celled bladders, the yeast will start excreting extra nitrogen in the form of Urea all over whatever they’re growing in.

Of course, the whole time they’ve also been excreting ethanol. It turns out, under certain conditions urea (more formally known as “carbamide” nowadays) and ethanol will combine like drunken evil “Wonder Twins” to form Ethyl Carbamate.

Front Cover of the book I ran into this as I was reading through my shiny new Wine Microbiology book, which has two pages on this yeast pee byproduct. An article linked to from fark.com recently reminded me of it and prompted this post.

To be honest, this seems a lot like the acrylamide media circus (compare the two links…) that popped up back in 2002. In both of these cases, we’re talking about a substance that occurs as a natural result of the preparation process rather than some new industrial chemical, and in both cases the processes in question have been around probably since prehistory. And in both cases, the real situation seems to boil down to something like “pay attention to your preparation technique, and if you try to live entirely on a diet of overcooked French fries and dessert wines, you might be at an increased risk for cancer.” QED. Or perhaps DUH.

Other than not trying to live on a French McDonald’s� diet, there are some things you can do when you brew to limit ethyl carbamate formation. Put very simply: don’t overfertilize your grapes because that can directly lead to unnecessarily high levels of nitrogen available in your wine, and don’t leave your bottles of brew in hot conditions for long, because ethyl carbamate forms faster in hot conditions.

There, problem solved. A more detailed “ethyl carbamate preventative action manual” may be found here. Meanwhile, I’m pretty sure our favorite drunken little micro-hedonists are too busy partying and making our wines and beers to be plotting our cancerous dooms.

WANT(?)

My parents, apparently comfortable with being microbiology “enablers“, ran into a digital microscope (pictured at right) that they pointed me to. It looks pretty nifty for the price, except for one issue: it only comes with three objectives, topping out at 40X. I can find marketing materials for this microscope, but no technical information beyond what’s on the company’s website (click image to reach that). Therefore, I can’t tell if the objectives are replaceable or not. If they are, the idea of picking up an inexpensive surplus 100X oil-immersion lens and ending up with a decent microscope with which to watch the Yeast Porn and such – on a nice digital screen, no less, rather than squinting into an eyepiece – has a certain appeal to it. The fact that the digital camera takes the pictures itself and only needs a computer connection to transfer files – and not even then if you use an SD card – means that I wouldn’t have to worry about ending up with something that requires Microsoft� Windows� just to look at some microbes (or post glamour shots of them to this blog).

However, I don’t think trying to view conjugating yeast cells or, say, Lactobacillus or Gluconobacter/Acetobacter bacterial cells at 400X would be very rewarding, so an oil-immersion lens is a necessity. And don’t let the “up to 1600 Power with Digital Zoom” thing fool you – it just makes the picture bigger and blockier, not actually more detailed.

So….do I WANT, or not? I sent off an email to Celestron asking about whether I could swap out objective lenses on this model or not. I got back the form “we got your email” email – we’ll see if I get a real reply from them or not. If so, I’ll update this post.

Speaking of which – still no reply from Bristol Brewing Company. Guess they’re either just not “nerd-friendly”, or the person who handles email queries is on vacation or something.

P.S. Dear Celestron – if you were to send me an evaluation model, I’d be happy to review it here on my blog for the ~~thousands~~ ~~hundreds~~ ~~dozens~~ pairs of people who read my ~~elegant prose~~ incoherent babbling…