Racking before end of fermentation?

[seanppp]

I saw advice for dry hopping from JC of Trillium Brewing on another forum. He suggested transferring from carboy to a keg just as krausen begins to drop (to ensure yeast activity/suspension for biotransformation), leaving the yeast cake and trub behind in the carboy.

This seemed odd to me, as I wonder if there will be enough yeast left over after the transfer to clean up the beer. He also mentions dropping the temperature to 62-64F for a few days, which also seems weird if you want the beer to clean up well (diacityl rest, etc).

Also, what does "just as krausen begins to drop" if you have an opaque fermentation vessel? Does it mean 2 or 3 gravity points before final gravity?

Any thoughts?

Below is the full text:
ideally, you carry out primary fermentation in a pressure vessel. conical is best so you can do all processes in a single vessel (minimize transfers & oxygen). you could do smaller ~4 gallon batches to allow for krausen, use fermcap in a corny keg, but in my experience, clogging the dip tube and poppits happens too often to make it a viable solution.

realizing that primary is going to be typically done in a carboy (preferred over buckets for that big surface area), you can do closed transfers by (slowly, low psi, use plastic carboy...NOT glass), he's a decent explanation:
http://www.homebrewing.com/articles/closed-transfer-system.php
make sure receiving corny has been purged with CO2 and has bagged hops weighed down w/ some stainless something or glass marbles to make sure the bag stays submerged. slowly vent gas on corny to allow beer to flow in from carboy, leaving trub and yeast cake behind.

***as mike said, timing of transfer: just as krausen is falling so there's still some yeast activity going on for biotransformation and oxygen scrubbing. BTW, yeast matters alot here...various strains have varying ability to create the incredible flavors from precursors in certain varieties of hops.

purge headspace a few times w/ CO2, then put a few psi head pressure on your corny keg, hold at ~62-64F for 4-5 days, then drop to ~34-35 (not too cold, you want to keep those delicate hop aromatics/flavor compounds in suspension!) and force carb. day after dropping temp, push out yeast/trub that's settled out. should be ready to pour in ~3-5 days, depending on the beer, force carbonation, etc. etc.

again, to confirm what mike said, w/ this process and equipment, no need to remove the hops.

good luck everyone! JC

 

[seanppp]

Bump

 

[Yooper]

The yeast "clean up" people talk about is the yeast digesting things like diacetyl. That is over by within 24 hours of the beer reaching FG, often earlier.

In the case of NE IPAs, the 'biotransformation' is the important part of the profile of the beer.

If you use a yeast strain that produces less diacetyl, and make a healthy size pitch of that yeast, you shouldn't have much or any detectable diacetyl to worry about anyway, so I wouldn't sweat it.

As far as the krausen dropping, you could just visually look and see when the krausen starts to recede. The SG wouldn't really need to be taken.

The thing is, to really get this procedure to work, you're really going to avoid oxidation so you'll want to do closed transfers (ideally under a bit of pressure, with a spunding valve), and so on, so you may not get the results you're looking for. The whole "biotransformation" thing is without the presence of oxygen.

 

[seanppp]

Thanks for the reply Yooper. I would look for the krausen to fall but I have an opaque fermenter so I can't see it. :-/ Do you know, based on experience, around how many points before FG the krausen tends to fall? Are we talking about 3 points or 20 points?

 

[Yooper]

Thanks for the reply Yooper. I would look for the krausen to fall but I have an opaque fermenter so I can't see it. :-/ Do you know, based on experience, around how many points before FG the krausen tends to fall? Are we talking about 3 points or 20 points?

No idea- it's likely yeast strain dependent among other factors. I've had some beers (mostly using wheat ale strains) where the krausen NEVER fell. But most fall, or start to fall about day 3 for me. It really would depend on so many factors that I couldn't guess.

 

[kh54s10]

I don't know the ins and outs of the procedure (never did it). But I have had Krausen start to fall on day 2 and others that have never totally fallen. I don't take gravity readings until I am ready to package the beer so I don't know the gravity on any of them when the Krausen starts to fall. Using Krausen falling as a determination of when to transfer seems highly inaccurate to me.

For an opaque fermenter, remove the airlock and look through the hole...

 

[oujens]

By chance, do you keg? If so have you considered fermenting in a corny keg? I recently made this switch using a spare corny that I rarely use. I settle for slightly less beer, but I can ferment under pressure, close transfer and take gravity samples through the liquid out post. You want to transfer and/or add hops with about 4-6 gravity points remaining. Yeast should finish just fine and consume all oxygen introduced. You definitely want a gravity measurement and not judging by the krausen.

 

[dyqik]

Why transfer to dry hop? Just drop the hops into the primary (the yeast will deal with the bit of oxygen admitted as they are still active, but minimize the amount of area you open - in a carboy or a bucket with a small opening available is best*), then do a closed transfer to keg (possibly with another dry hop charge - see Braufessor's North East IPA thread) after the initial dry hop period and fermentation are complete.

* I use a fermenting bucket with a hole drilled in the lid for a bung and a Speidel type airlock, because the grommets for narrower airlocks split and it was what I had to hand. That means I can dry hop in primary and siphon out without opening the bucket lid. Can't pressure transfer though.

 

[SlitheryDee]

This is one case where watching the airlock might be helpful. With an opaque fermenter you could identify when airlock activity is at it's peak and then transfer a day or two later.

 

[seanppp]

Why transfer to dry hop? Just drop the hops into the primary (the yeast will deal with the bit of oxygen admitted as they are still active, but minimize the amount of area you open - in a carboy or a bucket with a small opening available is best*), then do a closed transfer to keg (possibly with another dry hop charge - see Braufessor's North East IPA thread) after the initial dry hop period and fermentation are complete.

* I use a fermenting bucket with a hole drilled in the lid for a bung and a Speidel type airlock, because the grommets for narrower airlocks split and it was what I had to hand. That means I can dry hop in primary and siphon out without opening the bucket lid. Can't pressure transfer though.

If you don't ferment in a pressure vessel, you'd need to transfer to a pressure vessel (ie keg) to put pressure on the beer after adding the hops otherwise the subsequent fermentation will just blow all the oils out with the CO2 through the airlock. I have experienced this problem myself.