Friday, January 28, 2011

Yeast Harvesting, Ranching And Starters

I'm basing this latest yeast related post based on research and information found on the Mr. Beer Community Forum posted by experienced brewers and forum members like Dr. Dink, esheppy and others. Many thanks to those fellow brewers who have come before us and found time in their busy lives to test out new processes and then publish their research and experiences in hopes of helping others.  

 Any good brewing process has to produce consistently favorable results and this can only be achieved by putting a theory to the test and tweaking it along until it's perfected. As with all grain brewing I had read and researched yeast harvesting and ranching as much as possible before actually trying it out for myself. Once I had all the items required it really wasn't all that hard to do, it just meant incorporating a new process into my current list of brewing processes.

Yeast Harvesting - Eric Shepard

You can harvest a fresh batch of yeast from a batch of beer that has completed fermentation or a batch that is still fermenting, I decided to use the yeast from 2 Stout batches I was going to keg. A day before kegging my Barley Stout and Chocolate Stout I placed 6 six ounce mason jars and 2 twelve ounce mason jars into a 12 quart brew kettle boiled for 20 minutes, covered and let cool off overnight. 

 Boil Jars, Lids And Tongs For 20 minutes

1. Put the mason jars, lids, caps and a pair of tongs into a kettle filled with enough water to cover them and boil them for 20 minutes to both sanitize and remove oxygen from the water.

2. I let the water cool down for about 30 minutes before I used the tongs to fill the jars with the sterilized water and screw the lids on tight. I then let them cool off for another couple of hours before putting them in the fridge until cool overnight.

Carefully Lift Jars And Lids From Boiled Water

3. I had racked my stouts to secondaries 7 days ago and put them in the fridge to cold crash before kegging them so the temperature of the beer and the sterilized water in the jars were the same.

Transferring Stout To A Sanitized Keg Purged With Co2

4. After transferring the stout to my corny keg as I normally would I then poured the sanitized water from the mason jars into the fermenter and shook it to mix the trub up with the water.Let the fermenter sit for 20 minutes some separation may be noticeable at this point.

Trub At Bottom Of Mr. Beer Fermenter

Trub Mixed With Sterilized Water To Suspend Yeast

5. Pour the yeast/water mixture into the larger jars trying not to include any trub that separated out to the bottom of the fermenter.

After 20 Minutes Trub Settles To The Bottom

6. We don't want the trub we only want to harvest the suspended yeast so let the larger jars sit for 20 minutes again some separation may be noticeable at this point.

7. This time pour the yeast/water mixture into the smaller jars once again trying not to include any trub that separated out to the bottom of the larger jar.

Suspended Yeast In Smaller Jars And Trub In Larger Jar

8. Store the smaller jars of yeast in the refrigerator until needed for your next brewday then use them to create a yeast starter. You can make the starter by boiling a 1/2 cup of light DME in 2 cups of water for 10 minutes leaving the lid on and allow it to cool to 70F, this will create a starter with a gravity of about 1.040. Pour the starter and a jar of yeast into a flask and add it to your wort when it's at high krausen which usually takes between 24-36 hours.

Yeast Ranching - Dr Dink

You can ranch a fresh batch of liquid yeast by activating the smack pack as you normally do and letting it swell up according to the direction, usually between 3 to 24 hours. Next prepare the 1.040 OG starter wort by mixing 1/2 cup of light DME with 2 cups of water and and boiling it for 10 minutes. You can optionally add 1/4 teaspoon of yeast nutrient for a Mr. Beer sized batch to the wort before boiling it.

1. Smack the liquid yeast pack and allow it to swell as stated in the directions. (3-24 hours).

2. Boil
1/2 cup of light DME in 2 cups of water for 10 minutes leaving the lid on and allow it to cool to 70F.

3. Sanitize the stirplate flask and stir bar then pour in the cool wort and liquid yeast and cover with sanitized tin foil.

4. Place
stirplate flask and stir bar on the stir plate and allow to spin for 48 hours maintaining 70F.

5. Sanitize 6 small mason jars and caps then swirl the starter wort to re-suspend the yeast and pour an equal amount into each of the 6 mason jars and then cap them.

6. Store the jars in the back of the refrigerator until needed then create another starter (see step 2) and add this new starter to your brew when it's at high krausen (about 24 hours).

When only one jar of the ranched yeast is left we can then use it to make a new starter that will make another 6 jars of ranched yeast. Label these as 2nd generation yeast, it is possible to repeat this process to produce 5 or 6 generations from the initial liquid yeast smack pack.

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