Monday, May 15, 2006

Yeast 102

After my yeast starter fiasco (see Yeast 101), I was short a packet of yeast. I'd only bought enough for two batches, and one was splattered all over the walls of the hot water heater closet. Larry's is a drive from my house, it's over an hour round trip. I'd read about getting the yeast back out of the fermenter and reusing it. This seemed like a good opportunity to give it a try rather than spend an hour staring at the windshield of the car. Although, I did anyway...

Getting the yeast back from the fermenter and reusing it doesn't sound particularly difficult. It does require some 1 qt canning jars. After my last fiasco, I figured I should go ahead and get the right jars, after all, if this works out and isn't too difficult, it would be a big money saver (a smack pack of Wyeast is $4.25, the instructions I got from Wyeast say I can reuse the yeast 6 - 10 times before needing to buy a new pack). It turns out that almost nobody sells canning jars anymore. It took checking at 4 stores before I found some, $10 for a case of 12.

It was time to rack the batch of Cascade to the secondary and dry hop, which is the also time to gather the yeast. The instructions said to get 3 jars, sanitized, filled half full of sterilized water. Once the beer is racked out of the primary, pour the first jar of water into the primary, swirl it around with the hops, trub, and yeast, then empty the primary back into the jar. I had way more "stuff" than would fit in one jar, in fact, I was able to fill all three. I let them sit for about 15 - 20 minutes, until they were nicely segregated into layers. While they were sitting and separating, I got 6 more jars ready, then poured the top layer of the first set of jars into the second, and tossed the bottom layer down the sink.

The jars are sitting overnight in the refrigerator now. After about an hour, they are separating out into three layers, the top layer is water, the middle layer is the yeast, the bottom layer is junk. There's less than 1/4 inch of junk now, I'll see how it looks in the morning. The next step is to pour off the water, then pour the yeast layer into the third set of jars. The third set can stay refrigerated for up to a month. To use, pour off the water layer and pitch the yeast directly, or make a starter out of it.


I let the jars sit overnight (about 6 hours), poured off the water layer, poured the yeast layer into the third set of jars, and threw the bottom layer down the sink. I put them back in the refrigerator overnight again, there was a fairly thin layer of yeast on the bottom of each the next day. It didn't look like very much yeast to me, so I combined all three into one and made a starter out of it.


To make a starter: boil 2 cups of water, add 1/3 cup of malt extract, boil 15 minutes, cool to 70 degrees or so, then add the yeast. Pour into a quart jar, tighten the lid, agitate well. Store at 75 degrees F for a day or two before pitching. I read that a rule of thumb is to let the yeast sit for 1 day per month that the yeast is old, that is, if the yeast was harvested in April and now it's July, let it start for 3 days. Overall, this works really well, and is a big money saver. Since I started doing this, I've only bought 2 new packages of yeast for 12 batches of beer.


Later in life, I've gotten lazy. Well, I suppose I've been lazy all along, but now I'm lazier! The whole yeast washing thing is a lot of work. My current method is to get a 12 oz bottle of store-bought water, dump it into the fermenter after racking out the beer, swirl it around to get everything flowing smoothly, then pouring it into Mason jars. I usually get 3 jars out of a 10 gallon batch. I add one water purification tablet per jar. You can get these at REI or other sporting goods store. They kill any bacteria, but leave the yeast alone. These seem to keep for several months in the refrigerator with no problem.  On brew day, I get out 2 jars (1 per 5 gallons) from the refrigerator and set them on the kitchen counter.  By pitching time, they are at room temperature.  I give the jars a good shake to get everything suspended, then pitch and stir.