March Tech Topic Advanced Yeast Wrangling

[Don]

I'm going to try to uncover some of the mysteries of yeast next month.

Since I covered basic yeast and starters last fall, I would like to move on. I will have more handouts from last year if you are new or your dog eat your other copies.

I don't mind covering the basic again if there isn't much interest in advance yeast techniques.

I had planned on covering:
Harvesting yeast techniques
How to save and reuse yeast
Repitching on yeast-cake

I am open to what the members want, so post you questions.

[msjulian]

Don't know if I can be at the meeting or not but my question is this.

On 10/24/11 I poured all the yeast sludge from my Hefe out of my fermentor in to a sanitized mason jar. Put in the fridge until I was ready to rinse and re-pitch. 4 months later I was ready to use. I opened up the jar and gave it a good smell.. still smelled like good beer. I decanted the beer off the top and gave it a taste.. still tasted like good beer so I decided I was going to use it. I poured the remainder (400ml of beer/yeast/trub) in to a 2000ml flask with 1600ml of cooled boiled water. Swirled it up real good and let settle for 20 min. Decanted a little of the water/beer off the top and poured off 800ml of the creamy stuff in the middle in to a sanitized mason jar. Stuck that in the fridge to settle out. I now have a nice creamy white layer of yeast on the bottom (still settling out so I am not sure how much I will end up with) . So far so good...


Now for the real question (unless there might be some suggestions on any of the steps I have used so far). I was planning to build a starter to wake up and re-build the yeast to brew another Hefe. How much on the rinsed yeast cake should I use in the starter and how big of a starter should I build? Brewing a 6 gal batch of a standard Hefe.


I think that a lot of this is going to come from experience and a little bit of shooting from the hip unless you have the equipment to count yeast cells and check viability. After tasting a lot of your brews and seeing how you handle yeast I think you have a pretty good handle on how to get the most out of the yeast.

[msjulian]

Here is what I have after a night in the fridge. This is a quart jar and the first mark is 100ml so I am going to guess that the yeast cake is in the 50ml range.

wyeast3086.jpg

[Don]

The only things I've done different is tow rinse the yeast then add some sterial water before you lay it up. By just pouring the unrinsed yeast in a jar you brought all the other stuff with it and this will lead to unhealthy yeast
But you did what I would of by letting your nose and taste tell you that it didn't sour. Good job.
Also don't seal your storage jar tight. Unless you almost freeze the yeast it is still working. You might open the refrig and find a mess.

I keep all my yeast old and new as close to 34 degs as possible ( wyeasy say that that is the ideal short term storage temp) most refrg have @ 4 or so deg swing in them so unprotected a refrig set at normal yeast will get to 40 +. I use the ice packs I get when they ship me yeast and wrap them around the tubes and jars in the lowest part of the refrig.
To figure how many little yeasties you have without a microscope (which will be my next purchase- if anyone wants to donate to the Heisler toy and gadget fund)
Its easier with white labs tubes so that's how I'll explane it.

When you get a tube and it's fresh -less than 1 month old- look at the amount in your flask before you add your starter. That is @100 to 140 billion cells which is enough for a 5.25 gal worth under 1.060 SG.
That same volume of yeast after 1 month will be @20% less if stored under ideal conditions. And it goes down from there.

Roughly when you take the same volume From the carboy the yeast count is 1/2 the amount of yeast. Double the volume and you get back to the same as day 1.
Where this gets difficult is when and how you store the old yeast.
Under ideal conditions follow shat you normaly would do with fresh yeast and double.

As you said this is something you just need to keep good records (and pictures) and see how it comes out.
Please forgive all spelling and grammar I zm doing ghis from my phone. I recheck it after I get home.

[ArtCox]

If I use Fermentis Safale 05. in several different types of brews, how many times could I harvest and repitch without getting some weird mutation?

[sirgiovanni]

I personally never risk trub from the fermenter. I culture yeast and save trays of pretty small tubes from the initial yeast starter. When I get down to the last one, I re-cultivate from the original starter to fill another tray. My first starter is small and I step it up. The only risk with this is that every step can add contamination.

[Don]

Here are copies of my handouts for this months yeast tech meeting.
I'll have several copies at the meeting to handout, but to save a couple of trees can download your own.

[Dwayne_Delaney]

Good job! Thanks for the info and the presentation.

[sirgiovanni]

I was turned on the WHOLE TIME!

[Don]

I was turned on the WHOLE TIME!

And that's what worries me about you.

[msjulian]

Two Hearted Ale in the fridge now... Going to drink one tonight and see what I can get in to a white labs vile. Let me know when you drink this stuff and get the yeast.