Propagation and Starter Review

[Fletch78]

After reading the stickies, which is excellent detailed information, I've put together this plan to turn 1 tube of liquid yeast into 12.

I would appreciate any of you taking a quick look at the process and give me a thumbs up or down on the process, and make suggestions. If I had a stir plate, slants, or any scientific inclination, I'd use those. But since I don't.....

I'm basically making a gallon of crappy beer in order to have a clean unstressed yeast cake. I'd rather not add the hops at all, but the best article I read repeatedly mentioned their use, I can only assume it's for acidity.

1 gallon spring water (minerals)
1/2# light DME
3 or 4 hop pellets (for acidity)
1 tsp nutrient with DAP

12 eight oz mason jars with lids (3/4 gallon = 12 8oz mason jars filled to the brim)

Sanitizer


Pour spring water into pot, boil, cool covered, sanitize empty water jug and cap, and a funnel, pour 1/2 water back into jug and place in the freezer.

Boil remaining water with DME and hops for 15 minutes. Cover and cool.

Allow yeast tube to approach room temp.

Remove cold 1/2 gallon spring water from freezer, and shake well for 5 minutes. (Cold water absorbs 5x more O2 than room temp or warm water, according to a NOAA paper I read a while back).

Combine all ingredients minus 1/2 tsp of nutrient into the 1 gallon container to about 3 quarts and cap loosely and store in dark place at 70*F. Shake vigorously every hour or as often as possible for the first 2 days, adding the reserved 1/2 tsp nutrient after the first 12 hours.

After 4 days, tighten the lid down and monitor the firmness of the jug to ensure no pressure is building up. If pressure builds, relax the lid to allow escape of CO2. When no more pressure is building, cap tightly and refrigerate for 48 hours. (This allows more of the yeast to settle.)

Boil the jars and lids for 15 minutes in a gallon of water.
Decant 2/3 of the liquid from the jug (I might drink it) and replace with boiled/covered/cooled water to 3/4 of a gallon. (This removes much of the alcohol and CO2 and most of any unfermented sugar, this step can be repeated for even more purity. Think of it like a wash, but more of a rough hose-down)
Shake vigorously to get everything in suspension, fill the 12 jars to the brim, cap and refrigerate. Use within 6 months or re-propagate.

My impression is that each of the jars would have a similar cell count as the original tube of yeast, but I'm unsure of the viability of those cells vs what's in the store-bought stuff. Also, it is my understanding that for best results, each of these jars should be made into another starter instead of pitching directly into a 5.5 gal batch.


Thanks!

 

[Cheaton]

I understnad what you're trying to accomplish. I don't think the hops are at all neccesary. You're basically making a large starter. Also according to alot of what I've read it is best to "step up" your cell counts. In otherwords, do 1 litre, then put that into 2 litres, then put that into 4 liters, etc. INstead of starting with 1 gallon. I believe this stresses the yeast less?

 

[ajf]

That does not look good to me. The purpose of making a starter is to increase the cell count, but that method ends up by dividing the cell count by 12. Also, you would have to make a new starter for most of those 12 jars, as their viability decreases in the fridge.
I'd make a single starter using 4 oz DME, 1 qt water, and 1/4 tsp yeast nutrient. That should be OK for most ales, or you could double it for lagers.
Boil the DME in the water for 15 minutes, and add the nutrient for the last minute or so.
Cool to ~70F, pour into a sanitized growler or other container, using a sanitized funnel; and add the yeast. Cap the container with some sanitized foil and leave it at room temperature for 24 - 48 hours, giving it a good swirl as often as you can. (Shaking tends to spill the starter).
After 24 - 48 hours, you can pitch the whole starter into your wort, and convert the wort into beer. When it has finished fermenting, you will have a large amount of yeast. You can harvest that, and wash it to give you enough fresh yeast for several more brews. I usually collect enough yeast for about 4 brews, and make a new starter from the harvested yeast for each brew.

-a.

 

[Fletch78]

I would definately make a new starter out of each jar before going into a 5.5 gallon beer.

I can see what you mean by washing a yeast cake, but you are still dividing the cell county by X number of jars multiplied by Y number of decantings during the washing process. And because of my lack of control over a 5.5 gallon beer vs a 1 gallon jug, such as aeration among other things, I was just thinking it would be easier to "propagate" from the original tube into 12 smaller batches, than to try and wash a yeast cake which would undoubtedly have more stressed out yeast (in my beer, anyway ).

 

[Fletch78]

I understand that X being the viable cell count in the original tube would divide 3 times, those cells would divide twice, and those cells would divide once. That's how I did my math on cell count.

(X3+X)= Y
(Y2+Y)= Z
2(z) = final cell count

2z / 12 should actually give me more cell count per jar than I started with in the store-bought tube, minus what was lost decanting.

 

[Fletch78]

I understnad what you're trying to accomplish. I don't think the hops are at all neccesary. You're basically making a large starter. Also according to alot of what I've read it is best to "step up" your cell counts. In otherwords, do 1 litre, then put that into 2 litres, then put that into 4 liters, etc. INstead of starting with 1 gallon. I believe this stresses the yeast less?

I understand, but I am also under the impression you get another generation of yeast each time you do that, and after 5 regenerations, mutation is an issue. That's why I'm curious about making 1 big starter and dividing it for storage, to step up individually for each batch of actual beer brewed.

 

[ajf]

I don't dispute that you would end up with more yeast than you started with (even with the division by 12).
I just don't see the point in making a starter, then dividing into 12, and having to make a new starter with each of those 12 divisions, especially as some of those 12 will be approximately 6 months old by the time you use them if you brew every 2 weeks like I do. The viability of the yeast decreases much more rapidly if you package them, than it does when the Pro's do it.
I'd rather make a single starter, and pitch it into a batch, which gives the greatest chance of success.
When you're ready to rack, bottle, or keg, you will have more than 10 times the amount of yeast that you would have generated with your original 1/2 g starter, and you can harvest that yeast easily.
Using this method, you can start off with a much bigger starter, and you don't have to deal with really old yeast.

-a.

 

[Fletch78]

Anything unused within 6 months would be combined to repeat the process, and I'd only be on Gen 3.

 

[Fletch78]

The point in making a starter and dividing by 12 is to get 12 vials of yeast for the price of 1 plus DME and spring water.