I am looking for data on peoples' experience with Nottingham yeast, so that maybe I can figure out how to best utilize it in the future. Here's the background. I've used it several times now, twice pitching one pack and once pitching two packs (rehydrating according to instructions all three times). Here are the apparent attenuation (AA) data: Beer 1: 1 pack pitched, OG = 1.055, FG = 1.014, AA = 73%. Beer 2: 1 pack pitched, OG = 1.060, FG = 1.017, AA = 72%. Beer 3: 2 packs pitched, OG = 1.070, FG = 1.011, AA = 84%. As is evident, my experience suggest a substantial correlation with # of packs pitched and attenuation. Is this other people's experience, or is perhaps something else causing such wide variability in AA? What is your experience? Thanks and Cheers!
Did beer #3 have a more fermentable wort, i.e. less specialty/darker malts, longer mash time, and/or different mash temp?
Here are the data: Beer 1: Mash 90 min at 152.5 F, 28% Briess Pils, 69% Crisp MO, 3% crystal malt Beer 2: Mash 60 min at 153.9 F, 50% Pure Idaho Pils, 45% Crisp MO, 5% crystal malt Beer 3: Mash 90 min at 152.0 F, 92% Briess Pils, 8% crystal malt Cheers!
Two batches with it in the last 10 months, each was a stout, with ~5% crystal malt and ~15-20% flaked adjunct. (There were minor differences in grist) First batch, 1 pack pitched into 5 gallons wort that had been mashed at 156 at (calculated) pH 5.7. 73% attenuation Second batch, 1 pack pitched into 2.75 gallons, mashed at 152 and (calculated) pH 5.6. 76% attenuation
I don't have any data on Nottingham, but just looking at BrewCipher predictions based on wort attenuability, I get the following order, from highest to lowest attenuability. (I assumed C-40 for the crystal): beer #3 beer #1 beer #2 So I'd say it's likely wort attenuability played some part in this. But I don't think it accounts for the wide spread. If I take #3 (highest attenuation) as the "base" case and apply ratios based on BC results, I get... Beer # 3: 84% (same as you, because I'm setting it that way) Beer # 1: 83% (vs your 73%) Beer # 2: 79% (vs your 72%) Although I don't have any data on Nottingham, everything I've heard/read about it suggests it ought to get higher attenuation than #1 and #2 with relatively fermentable worts. That said, in my experience, pitch rate (with other strains) doesn't seem to influence attenuation much (if at all), unless the yeast is severely under pitched. I'm curious to hear what others have to say.
Numbers from a mostly extract batch, if that helps: 69% LME, Golden Light 9% Honey 9% White Wheat Malt 9% C-40 2% Special Roast 2% Roasted Barley 300L 1 packet Nottingham OG 1.071, FG 1.011 81.7% Predicted AA (per BrewCipher) 84.6% Achieved AA (per BrewCipher)
I don't have exact numbers to hand but I have consistently got high 70s with nottingham and gervin ale yeast, which are the same. It's interesting to see the difference you got in attenuation, your Beer 1 grist has probably half the diastatic power of beer 3. I wonder if it's a conversion thing? Although all the grists have easily enough diastatic power to convert properly
I have used Notty dozens of times and it gives me a VERY consistent 77-78% attenuation every dang time. I never rehydrate. So I have to wonder if maybe your rehydration method is killing some of your yeast, maybe there's chlorine present, or...? Are you storing your yeast in the refrigerator prior to use? Is your source shop a good reputable company? Is it mail order and experiencing very hot temperatures during shipping? Could be any number of things. Or could also be user error in measuring the gravity readings, hate to say, but, are you calibrating your hydrometer? If you are using a refractometer, that's a whole 'nother concern there......
Some interesting points and questions. Maybe I'll not rehydrate next time. I'm pretty sure my rehydration technique is sound, aside from perhaps some chlorine. I use carbon-filtered tap water, and I do boil, but I suppose there might be some chlorine left if my town uses chloramines (which I doubt, given it's a bit of a podunk town), but I really don't know. If I rehydrate in the future I'll be sure to use some metabisulfite (which I do use to treat my brewing liquor). Yes, I take care of the yeast -- in the fridge. LHBS is a good shop, the owner keeps the yeast in the fridge, but all yeast has to be shipped at some point, so unfavorable temperature conditions could, of course, have been a factor. Pretty sure of my gravity readings. I do use a refractometer, but I use the calculations derived by Sean Terrill. I have confirmed (with a number of batches) that the calculations quite accurate. For me the moral here is -- at least in the near future -- to pitch 2 packs. Cheers
Notty is my main work horse for yeast. Most of my beers use notty slurry which rip up sugars good. 1 packet will work, but I find using 1 pint of slurry where there is over half a pint of solids/yeast does burn down the sugars better. Pouring the wort onto a notty cake even better and quick. Used other yeasts in the past and still do for a few brews, but, give me da notty. Otherwise, I'll hear about it.
Possible but I really don't believe this is the solution. For me, a half a pack is plenty, assuming 5 gallons. Yes I am serious. And now... for the can of worms... As long as you're "pretty sure". Personally I have compared 5 different equations over dozens of batches to determine that Petr Novotny is the one who consistently gets the closest to a hydrometer, and his equation happens to be featured on Brewer's Friend, and includes good instructions for how to determine the Wort Correction Factor (for my own refractometer it is actually 0.99, not 1.00 or 1.04 as often touted elsewhere). Linky: https://www.brewersfriend.com/refractometer-calculator/ And if anyone might be interested to fall down the rabbit hole regarding refractometer calculations, a lot more guidance and discussion (arguments?) between myself, Sean Terrill, Petr Novotny, and others can be found here: https://www.homebrewersassociation.org/forum/index.php?topic=28544.15 https://www.homebrewtalk.com/threads/refractometers-and-final-gravity.667581/#post-8626423
Technically, every (unique) wort should have a different WCF, because its sugar/dextrin profile will be different.
Half a pack. You must be the Yeast Whisperer. I looked at the Brewer's Friend Calculator. Doesn't change things all that much, and not at all in terms of telling me that I'm not getting the attenuation I would like from Notty. Interesting discussion threads. I have been meaning to look in detail at the Novotny calculations. This looks like the motivation I need... Cheers!
