Is this enough yeast?

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Llamaman

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I recovered the yeast from two bottles of Bengal Lancer a few days ago and it’s fermenting nicely.
Will this be enough yeast for a 10L batch of moderate strength bitter, or do I need to keep going (and brew something else in the meantime...)
 
Looks like enough - that's about the same amount I did a full batch with and it worked. I kept a bit and started a new culture from and and it grew madly compared to the bottles. I then put little scoops of that into a 50/50 glycerine/water solution, shook it up and froze it in sterilised little jam jars and froze them. Pulling some out of those with the back of a spoon is enough to create enough for a full batch in a one litre starter. I didn't even step-build, but I might start doing it because I've been told it's not good for the yeast just going straight to 1 litre.
 
I'm sorry if this is long winded. I don't want to be a pretentious git, but in the interest of teaching a man to fish and giving the benefit of experience I'm going to waffle ... sorry!

Yeast slurry depending on thickness can quite happily be estimated at 1-3 billion cells per ml. Years of doing cell counts confirms this for me. Typically good slurry is almost always 2 billion cells per ml, but your mileage (process) and viability might vary. Slurry is what you get when you crash/chill the starter wort and off decant most of the clear portion at the top, leaving behind the solid layer at the bottom and then swirl it up with the little liquid that remains. If you have at least 40-60% solids before you swill it up you can quite happily (depending on strain) estimate it at 1 billion cells per ml.

This is handy, because standard pitch rates for ale is 1 million cells per ml per degree plato. A billion is a thousand millions and a litre is a thousand millilitres therefore 1 billion cells will result in 1 million cells in a litre. So basically you take the amount in litres, times it by the degrees plato and use that many ml of slurry consisting of 40-60% solids estimated at 1 billion cells per ml. To convert specific gravity/starting gravity into rough plato divide it by 4. So 1.040 becomes 10 degrees plato.

If your 10 litres of wort is 1.040 you'd need 100ml of slurry.

If 100ml seems like a lot bear in mind I use commercial pitch rates and like a 72 hour primary ferment. You'll likely get away with less, but you'll have a longer ferment, aeration becomes import and crucial if you intend to harvest yeast. There are so many fudge factors in this, but it'll work out fine 99% of the time. Your slurry may have more or less cells, but your viability might be lower or higher than expected. Your pitch might be off, but your volumes might be off. 1 million cells per ml per degree plato is a starting off point and a generous one at that. I've had fermentations complete fine with a quarter of that, it contains a healthy margin of error.
 
Going to give it a go. Got a quick 30 minute boil extract brew currently steeping.
If successful, will harvest the yeast from this brew to use in future.

Wish me luck!
 
Not wanting to hijack your thread Llamaman, but I also just pitched my first washed, built up single step London Fog yeast yesterday, and it also is bubbling away furiously with a nice big Krausen!
Despite all the examples of everyone else doing it, and how easy it is etc... the first one always has a slight trepidation aspect to it, so like yourself I'm glad to see it working as expected.
 
I was a bit concerned as there was no activity last night (I pitched in the morning) as I’m used to fermentation kicking off quickly with the dried yeasts I normally use.
But this morning it had a thick layer of foam so it clearly just took a few more hours to get started - I probably underpitched a little bit hopefully not so much to give any adverse effects.
I would have stepped up again if I had time but I only had one evening free to brew so it was do or die...
The next test will be to see how it gets on. I’ve heard the Fullers strain ferments quickly and floculates well so hopefully I can be drinking this in a month.
 
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