Not everyone knows but Dylan (pictured) has microscopic eyes and a rare ability to point out individual yeast cells with his finger.
I imagine that most blogs don't begin with an apology concerning the lack of blog posts. It turns out that my blogging ability is pretty much exactly like my jogging ability. Two years ago (three?) I decided I would jog around some of the blocks around my house which I did about 8 times. If my terrible memory is unlikely correct after about the 8th time I decided that I was pretty much as healthy as I was going to get and that my 'jogging' face looked a lot like my 'doing taxes' face. I think I also got lapped by the Postal Worker in my neighborhood. Anyway, you'll be happy to know that all of that energy is now being applied to blogging so you can expect a short burst of 'blog' face.
Yeast are on of the biggest mysteries of brewing. I mean what is yeast anyway? Well, yeast are in the Kingdom of Fungi, which seems like it would be a pretty neat Kingdom to be in. Yeast are quite small individually (measured in micrometers) but when they get invited to a beer party they invite lots of friends. When brewers 'pitch' yeast into fresh wort the yeast count can be anywhere from 6 to 18 million cells per ml depending on the gravity of the beer (or more for the biggest beers) but the yeast then self propagates into a much larger community. Brewers usually use one of two main types of Yeast - Saccharomyces Cerevisiae (ale yeast) or Saccharomyces Pastorianus (lager yeast) and these two kinds of yeasts are generally referred to as 'warm' fermenting or 'cold' fermenting respectively. Warm fermenting yeasts optimally feed and produce beer correct flavors somewhere between 62 and 72 degrees F. Cold fermenting yeasts do the same anywhere from 48-60. If I were a yeast my temperature range would be very narrow indeed. I find that I am most productive at 78 degrees between the hours of 9:30 and 11:00am from April until about 4th of July.
Yeast will convert wort to beer in a wider window of temperatures, but the flavor compounds and general health of the yeast will be affected - generally to the negative. Every beer style has general attributes that are exclusive to keeping correct yeast temperatures and populations - some of the flavor compounds that can develop due to a flawed fermentation schedule include unwanted ester formation (fruity), phenols (medicinal), autolysis (yeasty), and Diacetyl (buttery). Its important to note that many off-flavors are still a part of a healthy fermentation, but they remain below the taste threshold.
What do we do to prevent a wacked out ferment? Well, the best things you can do are to have a very healthy mother-colony of yeast, give them plenty of oxygen to build an even bigger colony to ferment your wort, and give them a nice comfy fermenter with a stable temperature. After fermentation its equally important to get the yeast off the beer (we don't filter so there is always a bit in suspension - you see our beer clarify over the weeks) since the food source (wort) is converted and nobody wants to be at a party that ran out of nachos. Then, get that yeast to the next party! Re-using yeast (conical fermenters have a nice little dump port at the bottom to run yeast out) is the name of the game. It costs us 600 bucks to buy new yeast for a 20bbl batch of beer. Yowzzaa.
Yeast are a lot more complex than I've described herein- but that goes without saying - except that I typed it. Way back in the day yeast were just an invisible force that made some beer good and some beer great. Now, yeast wear "Hi my name is ____" stickers and are grown up in labs across the world to perform exclusive tasks. So this is a thank you to all the billions of yeast cells out there that have contributed to making livers happy around the world.
Dylan Mosley is the Civil Life’s Brewer. He is also responsible for changing out the pirate flag every 8 months. His annual compensation package here is directly related to the amount of time his beard is a minimum of two inches long.