Methods of Yeast Farming

[dgrabstein]

I know a lot of brewers use the yeast cake from the bottom of a fermenter for the next batch.

Lately though, I have been using a different technique and I was wondering if anyone has experience with it's pros and cons.

I simply pitch 3/4 of my yeast starter into a batch and leave 1/4 of the starter on the stir plate. I then pour back in some 1.06 gravity wort into the starter to fill it back to its previous volume. Two days later I have a healthy starter again ready to pitch into a batch. Any reason this is bad? I haven't tried it much yet so I don't know if it works or not. Thanks for the input

 

[Culbetron]

It works fine if you are planning on separating your brew days by only 2 days.

If your brew days are farther apart, you would have an easier time pitching 3/4 of your starter (make sure to calculate your pitching rates correctly) then saving the 1/4 under some boiled, cooled water until you are ready for your next batch. Then add the wort to grow the starter.

The problem with what you are doing is that you are growing all this yeast really early which will have to be regrown as you get close to brew day. Yeast shouldn't sit around for more than a few days between growing in wort and getting pitched.

 

[dgrabstein]

Yes, that's exactly what I was assuming. I just have to brew a batch every 2-3 days now then, muahahahahahaha

 

[vinpaysdoc]

I got the idea for my yeast bank from this post:

https://www.homebrewtalk.com/entries/yeast-harvesting-novel-approach.html

I take a new vial of yeast that I purchase and make a 1.5L starter out of it. The vial has about 2 inches of a yeast cake at the bottom that equates to the 100 billion cells in the vial. I cold crash the starter, pour off most of the liquid, and then re-suspend the yeast. I pour the yeast in to a sanitized pot and use a sanitized 30 ml syringe to draw up the yeast and put it in sanitized test tubes of the same size. The starter often leaves me with 3-4 vials worth of yeast. I place the tubes in the refrigerator and allow them to settle for a couple of days. I then take them out, decant the fluid off the yeast cake, and replace it with sterile water. Since the test tubes are close to the same size that the original yeast came in (I also sanitize the original tube and put some back in there), I use the ratio of the yeast cake in the new tube to the standard of 100 billion in the original with a 2 inch yeast cake to estimate the number of cells in the new tubes. This gives me 3-4 vials of yeast that I can use to make starters. They are stored in the refrigerator until I need them for brewing. I record the date of their 'birth' on the calendar so I can plug that in to yeastcalc to get my numbers of viable cells. When I get to my last tube I simply repeat the process. I have only been doing this for about 3 months, soooo, I may find some problems down the line. So far, it has been working well.

You can find the Giant Soda Bottle Test Tubes (33ml) and Test Tube racks here:

http://www.hometrainingtools.com/giant-test-tubes-6-pack-baby-soda-bottles/p/CE-TTBSB06/

Just ask if you have any questions.