Underpitching Nottingham??

So, I always heard "1 packet per 5 gallons". Mr. Malty's calculator backs me up for a 1.055 OG batch. Everywhere says I need about 200 billion cells per 5 gallons. Danstar's site says "5-10 million cells per milliliter", which is about 100-200 billion per 5 gallons.

But Danstar's site says the Nottingham yeast has 5 billion cells per gram. That means an 11 gram sachet has only 55 billion cells. That means I need FOUR sachets for my 200 billion cells for my 5 gallon batch.

Further confusing the issue, Danstar's pitching FAQ says "1 gram per liter", of dry yeast. In a 5 gallon, (19 liter) batch, that's 19 grams, or nearly 2 sachets.

So, common wisdom and Mr Malty says 1 sachet. Danstar's FAQ says 2 sachets. Danstar's yeast count in their fact sheet says 2-4 sachets...

I know everyone just uses one sachet of dry yeast....but has this been discussed before? I couldn't find anything with search...

When I use dry, I pitch AT LEAST 2 packets, never just one. I always suggest a yeast starter, just like 90% of the folks here on HBT. It's really the best thing for you, but if no starter, at least 2 packets dry, if high OG 3 or 4 minimum. If Wyeast or White Labs, I use 2, 3 for high OG. Yeast starters will save you money, if you can't already tell.

weird never noticed that before. fermentis lists about the same count as well (6 billion/g). I've never gotten any off-flavors or much lag in going with 1 packet in similar batches, so I wouldnt worry about it, but thats definitely interesting.

HopsJunkie said:

I always suggest a yeast starter, just like 90% of the folks here on HBT.

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almost nobody here suggests making a starter with dry yeast, its generally not recommended.

Well, I should correct myself. You're right on that one, but I should clarify I was meaning with wet yeast there, just didn't convey that. Thanks for correcting me. I tend not to use dry, personally, just for the cost in buying 3 packets. I'm just a sucker for good attenuation and such.

5 million/ml is a common pitching rate on lower OG British ales. 10 million/ml is common for 1.048 lagers. There are about 20 billion cells per gram in dry yeast. If you don't rehydrate it well you can loose half of them. Lower pitch rates (within reason and with enough oxygen) won't have much effect on FG, it will just take longer and have more esters.

Even at 5 million/mL, you're at 2 packets per 5 gallons.

My issue is I make 10-11 gal batches....to hit the right pitching weight with liquid yeast, I need something around 4L of starter....I only have a 2L erlenmyer, so I typically use dry yeasts. But with the "correct" amount being 2-4 satchets per 5 gallons, I'm up to 8 damn satchets for my double batches....cripes that's 24 bucks in yeast alone, or 40 bucks if I use Safale...

I'm just surprised that the math shakes out that way, in spite of the "1 satchet is enough" I've seen bandied about, as well as the "a satchet has 200 billion cells" which I've read in a few places, (and his Highness Zamil seems to agree with, according to his calculator on MrMalty...)

I typically have low lag times, sub 12 hrs, and that's in a 60-65F fermentation chamber, but my beers always seem to finish high, even with a wort mashed at 151 or 150. I started thinking about yeast pitching rates perhaps being a part of it, which lead me to this.

Hmmm, experiment time. I'm making a 10 gallon batch this weekend. 5 gal I'll hit with a single sachet, the other 5 gal I'll hit with three sachets. May the best yeast win.

I think Jamil might be assuming you are rehydrating which would keep your active cell count in the range of two non-hydrated pack. The numbers may still be off, but I have a feeling that's part of the issue.

5 million cells/ml is five grams of dry yeast into 20 liters. It real simple to figure for 5.25 gallon batches.

Even if you use the equation form George Fix (the way Mr. Malty figures) 11.5 grams of dry yeast is more than enough for most beers. (0.75 million) X (milliliters of wort) X (degrees Plato of the wort) seems to be much more than is normally used in professional brewing. It's past the point where pitching more no longer produces more yeast or makes fermentation faster (that seems to be his point.) It's not right for every beer.

This is from JZ's site,

Mr. Malty said:

Some exciting work has been done on dry yeast lately. Reports are coming in of better quality, cleaner dry yeast. Personally, I really prefer the liquid yeasts, but the lure of dry yeast is strong. The biggest benefit is that it is cheap and does not require a starter. In fact, with most dry yeasts, placing them in a starter would just deplete the reserves that the yeast manufacturer worked so hard to build into the yeast. Most dry yeast has an average cell density of 20 billion cells per gram. You would need about 9.5 grams of dry yeast if you were pitching into 5.5 gallons of 1.048 wort to get the proper cell counts. (Recently there have been other numbers mentioned for cells/gram of dry yeast and folks have asked me why I believe there are 20 billion cells. I've actually done cell counts on dry yeast and they're always 20 billion per gram +/- less than a billion. Dr. Clayton Cone has also stated that there are 20 billion per gram, and other folks I trust tell me that 20 billion is correct. Until I see something different, practical experience tells me this number is correct.) For dry yeasts, just do a proper rehydration in tap water, do not do a starter.

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Sean Terrill did some rehydration experiments.
http://seanterrill.com/2011/04/01/dry-yeast-viability/

Malticulous said:

This is from JZ's site,


Sean Terrill did some rehydration experiments.
http://seanterrill.com/2011/04/01/dry-yeast-viability/

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That's all great stuff. Odd that Danstar says 5 billion/g and Fermentis says 6 billion/g, but Sean's test says 20+ billion/g.

Maybe I won't waste my extra yeast then....but Sean convinced me to rehydrate it correctly....

I read the US-05 pdf and it says "Dosage: 50 g/hl to 80 g/hl" then in the in the typical analysis it says "Viable cells at packaging: > 6 x 10^9 / gramme." Clearly they know you can get much more than 6 billion cells per gram.

Gotcha. 50g/hl is ~9.5g in 5 gallons, and the packets are 11. Guess they lowball the viable cells estimate so you don't *****? Still, why set SUCH a wide release spec?

Notty is my goto yeast. I always rehydrate it and only pitch 1 pkg per 5 to 5.5 gallon batch and it has never let me down. The math may be funky, but the proof is in the outcome. I've fermented it in the low 70's and also in the low 60's. Never had any off flavors, the job just gets done faster at the higher temps.