My Love Affair with Yeast

Yeasts are cool. Responsible for so many of the good things in life; bread, wine, anything pickled, liquors, ethanol, and of course – beer. Check out What Are Yeasts for a fully detailed description of those little asexual, unicellular fungi that are responsible for fermenting all of the alcoholic beverages that you love to drink.

Today I racked my Alaskan Smoked Porter clone to my keg and bottles. I thought that you might like to have a look at my Saccharomyces cerevisiae friends after they've been carousing for a week. Unlike humans, yeasts like to romance before alcohol. They then reproduce, and the entire neighborhood then has a blast (literally) while converting sugar to alcohol and CO2, and then they go to sleep – weary from their cycle but ready for the next party of oxygen and sugar to come along.

I carefully pried the lid off of my fermenter to see if any yeast were still present on the top of the beer. S. cerevisiae is termed a top-fermenting yeast; all of the action takes place in a frothy, foamy party on top of the beer. It is used in the production of almost all ales. This as opposed to Saccharomyces pastorianus, the bottom fermenting yeast that is used to produce so many of those lager, or pilsner beers that you may love.

The action under the lid was pretty calm; the yeast had pretty much partied out by Thursday (as determined by a non-bubbling airlock). What you see below is the top surface of the beer with gas bubbles and some thin, lazy yeast laying around on the surface. All of the remaining yeast has sunk to the bottom. You can see from the side of the bucket that the yeast foam was about an inch thick while they were doing their thing. That's pretty calm; I've actually had them having so much fun that they blew the airlock off of the fermenter and gushed beer all over my wife's basement floor. She still discusses these events.

The yeast ring on the side of the bucket was about 1" thick

I racked the beer to a 3 gallon keg and then made several six-packs of 12-ounce bottles. I put the Smoked Porter keg into my kegerator next to the keg of Belgian Wit Ale that I made last month. Here is a picture of the two of them getting along quite nicely together. Aren't they a good looking couple?

L to R on the bottom shelf - Alaskan Smoked Porter, Belgian Wit, CO2 Bottle; plus a couple of new sixes on the floor

For you geeks, the original gravity of my wort was 1.053. My final gravity measured today came in at 1.006 (both measurements taken at 68 deg F and then adjusted to 60 deg F). That is outstanding conversion, and gives me an alcohol by volume of approximately 6.2%. Yeah baby...that ain't no Coors Light! Here are some photos of my hydrometer measuring specific gravity in the beer. I apologize that they are not clearer; perhaps my wife will buy me a better camera and a Brew-Magic System for my bithday in 2 weeks.

Here's the hydrometer floating in its cylinder. Just the tip is showing above the beer (a good thing)

Here's the hydrometer close-up. You can almost make out "1.000" and then count down 6 clicks to 1.006

Lastly, here's a photo of the sleeping yeast at the bottom of the fermenter after all of the beer was racked off. It's probably ½" to ¾" thick. Although there are some hops and other sediments in the mix, if you compare the volume here to the original package I showed in last week's posting, you can see that the yeast truly multiplied and had a great time during their short party.

The bucket is empty except for the layer of yeast and sediment on the bottom

I ran my finger through the yeast layer; you can see it covered it up to the first joint

A handful of one of God's greatest inventions

Long live Saccharomyces cerevisiae!

Until next time...cheers!