Sunday, April 29, 2012

Making A Starter From Harvested Yeast

Last month I brewed a version of my of my Screwer In The Rye Lager pitching two bottles of East Coast Yeast ECY12 - Old Newark Beer™ yeast into a five gallon batch. The recipe is all grain with a 1.060 original gravity and at 59F it fermented down to a 1.014 final gravity in just under three weeks time. The fermentation took off vigorously with a short lag time and the beer was a huge hit with those lager lovers lucky enough to sample it before it ran out.

 Early on bottling day I filled a 16 quart pot with about a gallon of filtered water, put the lid on it and let it boil for about 15 minutes to sterilize it. I removed the pot from the heat to cool off leaving the lid on, this water would be used to rinse the yeast out of the fermentor. Once I sanitized my bottles and bottling bucket I put the pot in an ice water bath to get the sterilized water equal to the beer temperature. I transferred the beer from the fermentor to the bottling bucket leaving just the trub in the fermentor.

Then I sanitized a long handled plastic spoon, glass half gallon pickle jar, four pint mason jars and the lids to get them ready for the next step. I poured a half gallon of the sterilized water directly on top of the trub in the fermentor and used the spoon to gently mix the water and trub together to get the yeast into solution. After a minute of gentle stirring I carefully poured the mixture in the fermentor into the pickle jar filling it up to the very top and screwed on the top. I set the pickle jar aside and went back to bottling up my beer.

Stratified Layers In ECY-12 And WLP007 Yeast
 The healthy yeast layer we're really interest in storing has a nice light creamy color and it is located just above the heavier trub/cold break layer at the bottom of the containers. The ECY-12 lager yeast on the left is a medium flocculent yeast so more cells will tend to stay in suspension longer than the highly flocculent WLP007 ale yeast on the right. When washing any strain of yeast it's important to harvest a good mixture of both the more flocculent and less flocculent cells in each type of yeast to assure your future fermentations will continue to attenuate as fully as the original strain. 

Mason Jars Filled With Washed ECY-12

Buy the time I was done bottling my beer the slurry in the pickle jar had started separating into separate layers, with the heavier hop particles and dead yeast cells settling out first at the bottom of the jar. The very top of the slurry had a thin layer of something and in between the two was the larger layer of yeast. I laid the four mason jars out in a line and filled each one up half way then went back to the first jar and topped them all off in the same order. What was left in the pickle jar was mostly all gritty looking trub that I washed down the sink after screwing the lids on the mason jars, labeling and putting them in the refrigerator.

Freshly Rinsed And Stored Yeast
 Fast forward to this past Friday morning when I started off my day by brewing up a 1.040 batch of wort to use in my starter and taking a mason jar of stored yeast out of the refrigerator to warm up. A half cup of light DME mixed in with 1200 ml of filtered water some old dry yeast and boiled for 15 minutes was all it took to get going. Once the wort and yeast were at the same temperature I sanitized my Erlenmeyer flask, funnel, stir bar and decanted off most of the water from the mason. I shook the yeast and water in the jar to break up the flocs, get all the yeast into solution and then poured it into the flask topping the flask off with the starter wort. I dropped in the stir bar, sprayed the top of the flask loosely covered the opening with a piece of sanitized tin foil and set the flask on the stirplate.

ECY-12 Yeast Starter Before Pitching
Several hours later a nice layer of krausen had begun to form on top of the starter which peaked around eight hours later. I left the starter spinning on the stir plate until I was ready to pitch it into my wort the next day. I began the making the starter on Friday morning and pitched into a batch of wort around 3:00 pm the next day as soon as the wort cooled to the same 60F temperature as the yeast. This time I remembered to hold the stir bar in place with a magnet so it didn't end up inside the fermentor for a few weeks. The wort from the flask smelled good, there were no off odors when I pitched it and the fermentation started quickly. I checked the air lock this morning and there was already activity from the Co2 being created from inside the fermentor.

Aerated Rye Wort With ECY-12 Starter
The fermentor is now safely tucked away inside my fermentation chamber where I'll keep a close eye on maintaining a 59F temperature throughout the fermentation. It'll be a few weeks before I get to taste the fermented rye beer and compare it to the first batch I brewed last month but judging from the 1.060 original gravity reading, color and the taste of the wort before pitching the yeast this batch is definitely off to a great start.

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