Post Number: 607
Posted From: 188.8.131.52
|Posted on Wednesday, October 28, 2009 - 05:42 pm: ||
Just racked an Imperial Stout with an OG of 1.095 FG 1.020. That gives me about an attenuation rate of 79%. I was dissapointed with that until I looked at the stats of the yeast W1728. It gives this yeast between 69-73%. Still.........could I have dropped it further?
Post Number: 134
Posted From: 184.108.40.206
|Posted on Wednesday, October 28, 2009 - 06:18 pm: ||
Depends on several factors. How big of a starter did you pitch? Did you oxygenate? What temperature did you mash at? How many grains that contribute unfermentables (e.g. crystal and/or dextrin malt) are in your grist? I find I can almost always push my yeast past what manufacturers list if I give my yeast a fermentable wort.
With that strain, I'd say you are done. That really is excellent attenuation for that strain, let alone in a impy. Good work.
(Message edited by Marc_rehfuss on October 28, 2009)
Post Number: 7295
Posted From: 220.127.116.11
|Posted on Wednesday, October 28, 2009 - 06:33 pm: ||
Yeast attenuation rating make a lot less difference than the fermentability of the wort.
Post Number: 10875
Posted From: 18.104.22.168
|Posted on Wednesday, October 28, 2009 - 07:50 pm: ||
Denny's correct that other factors have even more influence than the yeast strain in terms of attenuation, but I have to give the nod to Marc here. I agree that 79 percent apparent attenuation is as much as you could expect for Wyeast 1728 in an all-malt beer. The only thing you could have done would have been to substitute sugar for some of the malt.
Actually, I think you will be quite happy with your F.G. of 1.020 for an 1.095 imperial stout. Big beers like this are supposed to have body and just a little residual sweetness.