This was posted on another board and I wanted to be sure people here saw it. Some great info…
The diacetyl rest on the Ale is interesting
Nice,
I had not seen a chart with their yeast and recomended beer styles before and the yeast characteristics table is great.
Fred
Very helpful. Thanks for posting it!!!
WOW, I have looked at their site a lot and never saw that page. Great info. I use their yeast a lot and love it. Now that I have a LHBS I have went back to White Labs and Wyeast but I have a few house recipes that always get the Fermentis. I always keep a few packs of the SA-04 and US-05 on hand. If you don’t have a LHBS and have to order liquid online this is a great alternative if you are using American Ale or English Ale yeast.
That’s awesome Denny, considering how I use 05. I’ll have to read this, and maybe take my beer to the next level of “sucks a little less”.
Interesting; though I always thought it was much better to rehydrate in sterile water, not wort, because of the increased osmotic pressure on the yeast cell walls from all the sugars.
Also, while we’re on the subject, here’s a nice read on rehydration and nutrients I found yesterday by Shea Comfort: http://www.yeastwhisperer.com/uploads/YeastWhisp_Yeast_Hyd_Nut_07.pdf
I believe that the only real difference between the two papers is that Shea encourages rehydrating at even higher temperatures (about 100F). I’m not sure if that’s specifically in reference to wine yeasts, though. He also discourages rehydrating in distilled or RO water, because the lack of calcium and other ions creates a reverse osmotic effect, from the inside-out of the yeast.
good stuff, thanks for posting it
ha ha that’s brilliant
In our club, the highest compliment you can pay someone’s beer is to say “it doesn’t suck”. Next is “at least you got the color right”! 
The ultimate kiss of death has to be labeling a beer “Drinkable”
A couple points I picked up on were that fact that ester production is related to O2 levels and pressure. A recent triple I did may have been less estery than I expected due to over oxygenation and/or not sealing the lid on the prmiary for the first week of fermentation.
I think there are two seperate things going on here.
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Initial oxygenation: This can have a big impact on ester production as it also influences yeast growth and acetyl coA use. It’s hard to isolate any one variable, but from what I’ve seen/read under-aeration can possibly increase ester production. The Clayton Cone Q&A that Denny has linked to before talks about this.
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CO2 inhibition: During fermentation, pressure/CO2 presence can impact ester levels. An open fermentation allows CO2 to dissipate. Ron Jeffries from Jolly Pumpkin has said that this gives him a more complex ester profile. He also uses shallow (square tanks), so pressure is lower. I’m not sure if there have been any studies on homebrew-size batches and whether tank geometry still affects ester production at the smaller scale.
I don’t think there could be any geometry effect at all, unless you were using an exceptionally tall and narrow fermenter. The pressure at the bottom of a 50 cm column of beer is like 5 kPa. That’s only 5% more than atmospheric at sea level. That might actually be a fun experiment: ferment half a batch at sea level and half at, say, 3000 feet where the pressure’s 10% lower. Of course, I’d have to drive like eight hours to /get/ to 3000 feet…
There might be something to open fermentation since you’d outgas more CO2 via diffusion, but I suspect you’d have to be using a pretty shallow tank in the first place to see a difference.
I have been wondering about open fermenters for some time.
Something like this on small scale:
Well, they are extremely worried about switching to cylindro-conicals in Belgium, due to the reduced ester profile from the taller tanks versus 1 to 1 height : width square fermenters. Check out BLAM for more info on this. CO2 inhibition from pressure is also scientifically documented in the commercial brewing world.
From the paper:
"If pressure is applied above 1 bar a formation of higher esters is visible. This
can also happen in tall fermentation vessels due to pressure. On the
Isn’t this saying the opposite about pressure & esters.
Also, when homebrewing, won’t using an airlock vs a non-sealed lid add pressure?
contrary, open or shallow vessels will give lower ester levels."
Geometry may have some effect, but at homebrew volumes I don’t worry about it.
My little 10 gallon batches in a cylindrical don’t have the pressure diff top to bottom as a 800 barrel fermenter.
I have been covering the neck of the carboy with AL foil for the first part of fermentation. When things slow down, I put on the airlock.
Yes, that is the opposite of what I have heard – that tall cylindro-conicals reduce ester formation.
http://www.scientificsocieties.org/JIB/papers/1992/1992_98_2_133.pdf
“The results of this study have confirmed that the formation of higher alcohols and acetate esters is inhibited by CO2 for all the yeast strains tested.”