ChuckieG
Member
So I'm brewing a London Bitter in two strengths using a parti-gyle method. This was supposed to be a Fullers ESB and Fullers London Pride, 10 gallons of ESB and 20 gallons of Pride. Targeted OGs were 1.058 and 1.047. This is an all grain brew, mashed at 149F. I didn't sparge enough and ended up with lower than anticipated volume after boil, and higher than targeted OGs, 1.08 and 1.056. I had prepared a 2 gallon starter from a fresh smack pack of Wyeast W1968 and pitched a little over a quart into each carboy containing about 4.5 gallons of wort, cooled to about 65F. Six days later, the strong brew is at 1.024, which equals 70% attenuation, which is normal for W1968. I'd like to get it down lower, towards 1.016-1.018 if possible, but for a 7.35% abv brew, 1.02ish will be ok. The lower OG brew, however has only attenuated 40%, to 1.034, or 2.89% ABV. This is problematic, unless it just takes longer and keeps coming down. Fermentation peaked after 4 days, and was never super vigorous. The starter was never super vigorous either. In previous similar brews, I've had this yeast blowing off like crazy but not so this time. Fermentation temperature has been steady at 66F. The only thing I did very differently this time from previous times is where I usually shake the carboys vigorously to oxygenate, this time I used a air pump and stone and bubbled each carboy for about 5 minutes. (I'm getting pure oxygen soon. I got a tank and aeration stones but still need to fill it and to get a regulator.) Any ideas or suggestions on what to do from here? I just added some yeast nutrient to the four carboys that are at 1.034 and shook them, hoping to crank up the yeast a bit. Just waiting another week I'm sure the FG will be lower, but I worry when I see the gravity remaining so high after the fermentation has slowed. Strangest to me is why would the 1.056 OG beer attenuate so much less than a 1.08 OG beer? I would have expected the opposite... Perhaps I should make up another fresh starter and add it and see if that helps? If oxygen is low that might not help. If I had my oxygen set up ready I'd jack that up but I don't. For my strong beer I'm thinking that I could select another higher attenuating yeast to attack the remaining sugars further in a secondary fermentation but I don't want to change the character of the beer a whole lot. Any ideas???