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?

[Ralph]

So... I made myself a whirlpool in the Jamil immersion chiller whirlpool fashion http://www.mrmalty.com/chiller.php

I only have a tiny 12v pump for recirculation (7L per min) so the flow rate and the whirlpool it creates are not huge. In fact I can make a better whirlpool by stirring!

However, it seemed good for recirculating my whirlpool hop additions, and when I started chilling it took the temperature of the wort down quicker than usual. Draining the wort there was a nice cone of hops and break left in the center, but still plenty of cold break sitting around the sides. I did like the cone of hops left in the middle and the extra speed it cooled the wort down. I may have to get a bigger and better pump at some stage but it does a good job even with the little cheapy I am using http://www.craftbrewer.com.au/shop/details.asp?PID=4630

[Matt Smith]

What a little cutie! Surely it serves its purpose as good as a Marchpump for 20-40L batches?

[Ralph]

Well the price is right... and you can grab a power supply for less than $20 and is easy to wire up. 1/2 inch thread BSP makes adding fittings easy. Works fine for transferring wort etc. Would be fine for mash recirculation etc.

[Matt Smith]

Nice, thanks for the tip. Ah, my wishlist is getting way too long.

[Grant R Baker]

I was reading an article on Brewsmith site today re the effect of whirlpooling (large batches as it was) and the extra IBU from late hops it causes.

 

They were talking about 200l plus size batch and also mentions it is less of a problem for smaller brew (30l) but the effect of a 20minute hot whirl pool extra 35IBU more than desired from late addition hops (last 15 minutes) and to a lesser extend initial hops.

 

Just though you might find the info of some use. If you search their forums on 'Using Beersmith to calculate large brews' you'll find it.

[Ralph]

Yep, you definitely get more ibu out of hot whirlpool for 20 min. Might take a few brews to figure out approx what my system adds in the way of ibus, but the first batch turned out great. Heaps of great hop flavour! I did allow for more ibu from the whirlpool and so dropped the overall ibu of the beer.

Have just done a Mosaic pale ale with a good whirlpool too. In the fermentor at the moment. I am looking forward to tasting that!