Using washed yeast - Wyeast 1056

[catalanotte]

Looking for feedback on my first attempt at using washed yeast. I washed the Wyeast 1056 out of the primary from a batch that fermented very aggressively (88% attenuation). Washed once with distilled water, got a nice clean sample. Used a jar of washed yeast with about 60ml of solids (2 weeks old), poured off clear liquid, and made starter with a pint of sterile wort at a SG of 1.044. Good active fermentation evident within a couple of hours. Pitched after about 6 hours into wort at 1.057. Slow start to fermentation, and continues at a very slow but steady pace. I am concerned because this yeast isn't developing the high krausen and level if fermentation that was apparent with the first use. Does this all sound normal?

 

[shtoive87]

What is the temp of the fermentation and did you aerate? Slow start could be due to temp shock or yeast taking their time to multiply. Also what was the abv of the original batch you harvested from?


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[catalanotte]

Same general conditions as original batch. Pitched in the mid 80s (too warm, I know) but so was the first batch with this yeast that went nuts. Yeast was washed from a 5.9% batch with a 29 IBU. Should have been decent conditions but I am new to reusing yeast.

 

[catalanotte]

You also asked about aeration. I gave the carboy a solid shake which has always been enough.

 

[flars]

You probably under pitched so this fermentation will be a little slower. A good pitch rate would have been 199 billion cells.

I estimate 1 billion cells per ml for rinsed yeast. 60ml two weeks old would have approximately 53 billion cells. The starter, if it completed, would have resulted in a growth rate of 1.4 to finish with 141 to 148 billion cells.

 

[catalanotte]

Using the mr. malty calculator for pitching from slurry, I came up with 4.5 b/ml for "thick solids" and a 77% viability (11 days old). See original picture for what I measured as "thick solids". With a pitch rate of about 200 b (same as you stated), this worked out to 58 ml of "thick yeast". I figured a starter with 55 ml would be good. Looks like the big difference in the assumed cell count of the washed yeast. If I make a quart starter with say 100 b cells, what can I reasonably expect to have a day later when I pitch?

Brewed 7/28, getting a bubble every 3-4 s through airlock so it looks good now. Not going to mess with it to check SG until I rack it in a few days (5 bubbles per minute). Silly rule, but has worked for me.

 

[flars]

Using the mr. malty calculator for pitching from slurry, I came up with 4.5 b/ml for "thick solids" and a 77% viability (11 days old). See original picture for what I measured as "thick solids". With a pitch rate of about 200 b (same as you stated), this worked out to 58 ml of "thick yeast". I figured a starter with 55 ml would be good. Looks like the big difference in the assumed cell count of the washed yeast. If I make a quart starter with say 100 b cells, what can I reasonably expect to have a day later when I pitch?

Brewed 7/28, getting a bubble every 3-4 s through airlock so it looks good now. Not going to mess with it to check SG until I rack it in a few days (5 bubbles per minute). Silly rule, but has worked for me.

I'm not sure what they mean by thick yeast without taking into consideration the harvest date.

I updated the yeast volumes available in my spreadsheet for the harvested yeast I have stored in the frig. This is also yeast without any hop debris. A jar of 3rd generation WY1056 lost 50ml of volume in a period of three weeks to five weeks due to compaction. I didn't save the date of previously recording the volume. The yeast in this jar went beyond thick. It was solid. The yeast was almost four months old.

The longer you have stored yeast the more compact it becomes. The longer you have stored yeast the greater the viability loss.

That's the reason I estimate one billion cells per ml and use the production date for viability loss.

I like to use the Brewers Friend pitch rate calculator for starters.
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/