Dry Yeast Pitching Rate

[sir_brewski]

I've done a little research and can't seem to find anybody who follows a precise pitching rate when using dry yeast. I've read a few examples of brewers just dumping 500 grams in each batch anywhere from 10-15 bbls. The vagueness of this method bothers me. On top of this, it sounds as though they are drastically underpitching considering this product spec sheet for safale s-05:

http://www.fermentis.com/wp-content/uploads/2012/02/SFA_US05.pdf

It claims each gram has 6 billion viable cells. Knowing this It seems that I should be using around 19.5 grams per barrel, per degree plato ((~117,350 ml per barrel * 1 million) / 6 billion cells per gram).

Am I missing something here?

[RobW]

I use 1 500g package per 10bbl.. Not by any calculations, just by what I used to use at a previous brewery and it works well at that pitching rate.

Rob

[wailingguitar]

I also use 500g pack per 10bbl (rounding up)... I got that figure from John Mallett years ago and later my fermentis hawker reiterated that figure, so that is what I have always gone with. S-04 is my yeast of choice and with that ratio I see good starts every time

[jwalts]

Your calculation is right, but the numbers provided by dry yeast manufacturers are often guaranteed minimums and actual cell counts are usually far higher. I've had a lot of pilot batch success by assuming that dry yeast contains 14 billion viable cells per gram (20 billion cells per gram at 70% viability) and targeting 0.75 million cells/mL/P for ales, but I haven't tried dry yeast in full-scale batches. Assuming 20 billion viable cells per gram - a number I've seen in several places - gave me inconsistent results.

Joe
Narrows Brewing
Tacoma, WA

[nateo]

This might be of interest to you: http://koehlerbeer.com/2008/06/07/re...-clayton-cone/

That "20b" number is assuming optimal rehydration. If you're just dumping the dry yeast in the wort, at pitching temp, you're probably cutting that number down quite a bit.

[jwalts]

Good point. I rehydrated the yeast, though. The article also mentions that room-temperature storage causes viability to drop.

[callmetim]

I use 2.2 billion per gallon per degree plato. Been doing that for a couple of hundred batches and it works well. I do not rehydrate just dump on cooled wort.

[sir_brewski]

This might be of interest to you: http://koehlerbeer.com/2008/06/07/re...-clayton-cone/

That "20b" number is assuming optimal rehydration. If you're just dumping the dry yeast in the wort, at pitching temp, you're probably cutting that number down quite a bit.

Excellent article, Thank you.

[DageraadBen]

You forgot the part where you should multiply by the degrees plato. 117,350 ml/bbl *1 million * gravity in plato / 6 million cells/g = pitch rate in g/bbl.

[TemplarBrewing]

Harvest

Are you harvesting that yeast or just chucking a new one in there each time?