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Yeast Pitching Rates


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Hi all.. I have a question. Putting a brew in based on a CPA can but im messing with it a fair bit.


Brew =


CPA can + BE2 +

250g light crystal + 150G carapils + 150g wheat malt

400g DME + 150g dex

hop tea of 15g amarillo

15g cascade and 15g amarillo dry hop after high krausen

to 25lt


expected OG is 1050 approx. expected FG is 1010 (I like em dry)


Question is, how do I determine how much yeast to pitch.. Im pretty sure the 7g packet that comes with the kit will leave this brew underpitched but I want to make sure I have enough viable yeast to do the job.


Does coopers have some tools available for calculating this?


how can I calculate how much active yeast I need?


as I understand it, a higher gravity wort will need a more active yeast population than the kit yeast can provide without a starter .

There are a few resource around to help with these calculations that I am familiar with, none I believe to be endorsed by this site.


so I am wondering if somebody can point me in the direction of some site sponsered/endorsed calculators for yeast pitching rates to gravity ratios?


I generally use Mr Malty, it has been suggested to me from a site moderator ,(I feel) incorrectly, that viability rates were assumed to be the same regardless of style.. I would like to add to this that in this particular calculator that viability can be adjusted to suit. indeed age to viability ratios exist and are not too far off the mark.


Sooo.. to shorten the rant.. based on the recipe, how many 7g packets of kit yeast (or billion cells if you like) do I need to finish and propperly attenuate this wort?



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In my opinion (and people will probably disagree), the kit yeast alone will be fine. I've done brews using the kit yeast with high OG's and they've attenuated just fine.

I've done a real ale with a kilo of dried malt, half a kilo of brew enhancer, a few hundred grams of crystal malt to a volume of 22 litres and used just the kit yeast, it fermented right down to 1.008. As long as the brew can isn't nearly out of date, the yeast will be good, you brew will attenuate fine, the beer will be nice, and you'll be happy... all of course in my opinion. [joyful]


As for a pitching calculator, i've never used one so I'm not sure where to find one...[pinched] ... surely someone else will know though


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I really want to be able to calculate it. especially for higher OG worts.


It doesn't feel right just saying "oh that 7g packet will do" especially when you vary from the 'kit and kilo' to a more specialised brew.


To be honest this question has really spawned from another thread I didn't want to derail or take further it's original topic so Iv'e started this one.


ie how to calculate the required amount of viable yeast cells for a particular OG of wort.

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To be honest, I'd like to see one as well. However, I think Mr malty is about as close as it gets for now.


You can always step up the yeast or pitch another packet but as you say, that is not the answer you are looking for. If there is someway to tell, I too would like to know.


The following was taken from the Wyeast Lab Website


Anytime you are pitching yeast into a harsh environment (high gravity, low temp) you need to add additional yeast. A rough rule of thumb is to double pitch rates above 1.065 and triple pitch rates above 1.085. Or, more technically, a million cells per milliliter are needed for a 20degree plato (1.080 specifice gravity) beer, or 3 Activator packages for a 5 gallon batch. It is also important to remember tht it is more difficult to get oxygen into the solution in a high gravity wort.

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