Could I get a sanity check on my starter?

[user 209521]

I've taken the cake (US-05) from my last brew, a 5 Gal ale, which came out good btw, washed the yeast and split it into 5 jars. For my brew in 2 days time I have taken one of these and put it in with a 1000ml starter and put it on a stir plate. I'm guessing this will allow time for the yeast to multiply up to something capable of fermenting.

If this works OK I'll do the same again with that cake, keeping not of the generations, maybe go for 5 generations from each of those original 5 jars. Plan is that as long as I'm using US-05 I'll be self sufficient for yeast.

But, from a 5th of a cake, with 1L of wort and 2 days will I be up to a descent pitch rate for a similar 5 Gal ale?

 

[SpeedYellow]

Wow that's a lot of effort just to save $4. But the answer is yes probably. You should play around with the yeast calculators to get an idea how much yeast you have at the end of fermentation (I.e. a 5-gal starter) then you cut that in fifths and compare that to what you need for your next batch.

But why would you save the yeast cake and make a starter with it? Seems like too much trouble -- personally I'd just save a bigger bit of the yeast cake and skip the starter. Just seems too complicated. And I'm in the camp that thinks yeast washing is a waste of time, so I won't even go there ...

 

[user 209521]

I can see where you are coming form but I was thinking 5 jars x 5 generations x $4 = $100 + the fun of it + no lag

 

[CB_in_Tokyo]

But why would you save the yeast cake and make a starter with it? Seems like too much trouble -- personally I'd just save a bigger bit of the yeast cake and skip the starter. Just seems too complicated. And I'm in the camp that thinks yeast washing is a waste of time, so I won't even go there ...

It depends how often you brew. Sometimes making a starter can be more about yeast health and viability than just about cell counts.

To the OP. I live in Japan and have to manage yeast as my options here are quite limited. In my most recent batch I used yeast that was washed and separated like yours back in February. I used three mason jars worth (decanted) into a 2.5L starter (I do 10 Gal batches), and then checked with a Hemocytometer afterwards. While I forget the exact cell counts I definitely had enough viable yeast and fermentation took off well.

I would definitely run your numbers through a yeast calculator, and your pitch rates are dependent upon your OG, but as an estimate I'd say you are are at least in the ballpark.

 

[user 209521]

I struggled with the idea of using a calculator for this until I realised that my last batch was effectively a 23L starter. All seems to work out, my target should be 214 Billion and my process seems to end up with 245 B. I guess this will probably be my first over pitch but I guess 14% could be seen more as a safety margin rather than over pitch.

Thanks for your help guys.

 

[WoodlandBrew]

But, from a 5th of a cake, with 1L of wort and 2 days will I be up to a descent pitch rate for a similar 5 Gal ale?

A starter made with 100g of DME will grow between 100 and 150 billion cells dependent mostly on the amount of FAN. [1]

The cell density of settled slurry is about 1.5 billion cells per ml. Viability doesn't drop much over time in the refrigerator.


[1] Schulze, Ulrik, et al. "Physiological effects of nitrogen starvation in an anaerobic batch culture of Saccharomyces cerevisiae." Microbiology 142.8 (1996): 2299-2310.

 

[Calder]

As a suggestion. Make your starter a quart bigger than needed. Once starter is done, swirl it up and let it settle for about 15 minutes, then take a quart off the starter into a separate container, place in fridge to settle out yeast.

With this quart you have taken off, you can decant most of the beer and store in an 8 ounce jar. This is a relatively small amount of yeast, and will keep in the fridge for months ........ even a couple of years.

Then with the current yeast, just take about a quarter of the cake for the next brew - no washing, no starter. Use this method for about 5 generations, ........... then when you want fresh, use the stored yeast to make a starter ..... and make it bigger by a quart again to save some for the future.

This way you can keep the strain going for years with little mutation.