Hitting FG target AND diacetyl resting

[mthhurley]

I've struggled with something that maybe someone can clarify.

Let's say I'm cloning a big'ish IPA, say in the 1.08 to 1.09 range OG.
The recipe calls for an FG of say, 1.021 or whatever.
Being an ale, I like to leave it a couple extra days to mop up the diacetyl.

However, what I pretty consistently encounter is the yeast doing a better job than I expected (or better than the recipe calls for). This last brew I have in secondary had an FG target of 1.021 per the recipe and within 4 days in a temp controlled fermentation, I was at 1.017 and it was still fermenting.

How do I "stop" this, without taking it off the yeast because I want to leave it for a diacetyl rest?

Thanks,
Mike

[Beertastic]

I would let it finish. 1.021 FG will tend to make a cloying double ipa. You should, if you haven't already, listen to the imperial ipa Jamil Show. The bjcp guidelines also list the FG below that (although only by a little).
http://www.bjcp.org/2008styles/style14.php#1c

Beertastic

[BenTheBrewer]

Is this all grain or extract?

If it is all grain I would mash at a little higher temp. That will leave less fermentable sugars in the wort.

I would also maybe try using a less attenuating yeast. Say Wyeast 1968 London ESB.

One last thing is try to ferment around 65 or so for a few days and then ramp up the temp to about 70F nearing the final gravity. Not really sure about that one though... That just may help clean up diacetyl.

Hope this helps.

[mthhurley]

Ok...That was meant to be an example.

Let's say the target was 1.019. I could likely have let this thing ride down to 1.015 if not lower.

Point is, if the clone recipe says x and my FG is heading toward < x, what if anything can I do to halt it while still wanting a D-rest?

[Sathington Willoby]

It's not really possible to stop the yeast from fermenting sugars and turn their attention to diacetyl. They want to eat the sugar first.

[mthhurley]

Is this all grain or extract?

If it is all grain I would mash at a little higher temp. That will leave less fermentable sugars in the wort.

I would also maybe try using a less attenuating yeast. Say Wyeast 1968 London ESB.

One last thing is try to ferment around 65 or so for a few days and then ramp up the temp to about 70F nearing the final gravity. Not really sure about that one though... That just may help clean up diacetyl.

Hope this helps.

All grain, good idea on the mash temps, but again, following a clone recipe to the T.
Not willing to change the yeast all the time cause if it's a clone, I'm trying to match a profile.
I did the ramping thing on this one. 68--71--74. Perhaps by ramping to 74, I induced the additional fermentation

[Travisty]

Everyone's system will be a bit different. If you find that you attenuate too far using the recipe's mash temperature, raise the mash temp next time you brew the beer.

[siwelwerd]

All grain, good idea on the mash temps, but again, following a clone recipe to the T.

+1 on the above that everyone's system is different. Don't be afraid to adjust mash temps and fermentation temps to achieve the desired results.

With a clone recipe, what's most important is the end result, not how you got there. Don't be afraid to tweak the recipe to get results that match the clone better. Remember, whoever developed the clone recipe did so knowing that that recipe with their process on their equipment would produce the result they are looking for; you only have the recipe, not their process nor equipment, so you should be prepared to tweak things as needed to get the beer you are looking for.