Hot whirlpool - DMS question

[Ralph]

So by my current understanding, boiling the wort drives off the precursors to DMS which could create unwanted flavours in beers.

I have been looking at how a few American breweries make APA and IPA and there has been a couple of mentions of whirlpooling the hops with hot wort for up to 20 min before cooling.

So far I had been thinking that having the wort hot would be creating the DMS precursors and this is the reason that people chill the wort as quickly as possible after the boil, but if these guys are swirling the wort around hot for another 20 mins and still making fantastic beer then I am guessing that swirling hot wort around for a while afterwards to extract hop goodness is ok?

If you boil vigorously for an hour or 90 mins does it exhaust all the stuff that would make DMS or is something else going on?

[Horace]

There wouldn't be too many commercial breweries that whirlpool for less than that, but their wort will stay hotter for longer. Therefore more hop bitterness...

For a 90 minute boil about 3/4 DMS is driven off. More is removed with a vigorous fermentation. With extra hop flavour any DMS will be less detectable.

[Grant R Baker]

hmmm this site Link mentions that boiling removes Dimenthyl Sulphide but as long the the wort is hot more is produced, so slow cool might be avoided.... thus the long whirlpool may be counter to the idea of lowering DMS.

It also mentions that leaving your brew uncovered helps remove DMS but fails to point out all the bugs the fly in.. Special Reserve.

I am very guilty of only 60 minute boils on most of my ales... I think I might step a few recipes up to 75mins to see if it makes a big difference, especially the lighter brews (blondes, saisons, bitters)... but I have noticed that the Scotch Ale I brew for 70mins has more burnt caramel notes than a similar recipes at 60mins.

[Ralph]

Have been reading more and came across this article which has interesting info.

http://morebeer.com/brewingtechniques/library/backissues/issue1.4/b...

To minimize oxygen uptake in a whirlpool, the inlet should be placed one-quarter to one-third of the way from the tank bottom (see Figure 3). The rotation about the vertical axis should continue for 20-40 min after the wort is in the tank. As the whirling action slows, the trub, which is heavier than beer, forms a fairly hard conical cake at the center of the bottom of the tank. If the time the wort is left standing is too short, separation will be incomplete; too long a stand, and the risk of infection rises and the breakdown of S-methyl-methionine continues, raising dimethyl sulfide levels.

[Grant R Baker]

So if you have a conical fermenter just dump your trub after 12-14hours? Before the yeast really gets going.

I have read the link a few times... only real reason I saw for removing the trub was "Effective removal of hot trub before fermentation is critical because the trub can smear the yeast's cell walls, impeding the transport of substances in and out of the cell, which can lead to head retention problems, poor flavor stability and harsh bitterness in the palate of the beer."

I can see the benefit of trub removal for light ales and lagers, but some of the characters mentioned above are desired in some beers (although in saying that, lagers often have higher DMS than ales). 

[Ralph]

The whirlpool has a couple of other things going for it. Mechanical action stirring the hops in hot wort should extract plenty of flavour from them... especially if you are adding hops to the whirlpool that are not being boiled (i.e. the nice volatile flavours are not being driven out the top by the boil). Also the whirlpool means that once the chiller is chilling it will drop the temperature quicker.

I do have a conical fermentor, but I am looking at the whirlpool mainly as a way to get more hop flavour into the hoppy beers. For standard beers it will be a way to cool the wort to pitching temp even quicker than usual. The Jamil type immersion chiller whirlpool seems to be a good option for both these objectives.

[David Williams]

I have a whirlpool inlet welded into my kettle and it definitely helps to cool to wort down quicker with an immersion chiller. It also creates a reasonable cone but I find this breaks down as the wort is drained. I've read that the good cones you see pics of are hot break only (no chilling aussies), cold break material doesn't stay compacted. How true this is I'm not sure, but I always chill and the cone tends to break apart which rather defeats the purpose.

It's interesting how discussions around retaining hop flavour/aroma have gone from chilling quickly and locking in the flavour to hop standing anywhere upto 80mins. 

[Druid]

Re.DMS formation/removal:

Commercial breweries usually have wort at >90 deg C sitting in the whirlpool for periods of longer than an hour while they a) circulate and b) while it is being transferred through a plate chiller to the fermenter.  As an example, all brews done at Steam are done this way. So I do wonder how much of an issue DMS formation really is, particularly if you achieve a healthy fermentation.  I've certainly never experienced it, even on 4% beers where off-flavours have nowhere to hide. And I usually have the top of the BK 90% covered and also regularly do hopstands with the lid on.

Re.hopstanding after flameout or in the whirlpool: 

I've done a beer that had 2 consecutive hopstand additions of 40g each of Amarillo for 30 minutes each after flameout - as for the hop character it imparted, I got enormous flavour but not so much aroma (which I added through dry hopping). Also, no sign of DMS.

[Chad Keven]

hey sorry to barge in on this but is whirlpooling a substitute for hop blockers and inline filters? i'm looking to upspec soon and trying to decide which way to go, id rather go for the whirlpool i cant be bothered with things blocking up. up untill now ive used hop bags, which has done the job so far.

thanks

[Druid]

It doesn't have to be high tech - most home brewers do it by just stirring the crap out of the cooled wort in the kettle until a whirlpool is achieved and then leaving it for 20 or 30 minutes until the circulation stops. The circular motion encourages a shallow cone of trub to form as the break settles. You then just siphon from the edges as the level of wort gets low to avoid sucking up break.

in my experience, it makes it easier to get more clear wort out of the kettle but you will still end up getting some break.

Commercial brewers do it while the wort is still hot, before they pass the wort through a plate chiller and it gives them an opportunity to add more hops while the wort is still hot - hence the term whirlpool addition.

[Chad Keven]

Thanks, whirlpool it is then I will be making it to be operated hot

[John H]

I use a low tech approach - sanitised spoon to stir both for flameout hop additions and chilling. Stirring while chilling seems to be HEAPS quicker.

[Grant R Baker]

I am starting to think a hopblocker filter directly attached to the ball-valve entry may be the easiest way to remove trub.

My 56L brew pot hasn't the room for anything too outrageous... especially when the immersion chiller is in there. I might have a lookc around the Stainless marine filters stuff.