[mtnandy]

I am planning on brewing 5 gal of a Duvel clone this weekend. 80% pils malt and 20% sugar. I have heard that the great head retention is due in part to the mash schedule. Is this true? If so, what mash schedule produces the strong head? How do I emulate it if I'm mashing in a coleman cooler (blue, of course)? Or is single infusion at around 147F sufficient?

[dbeechum]

I suspect the great head in duvel is less due to the mash and malts and more due to the hops - particularly tetra hop extract.

[andyi]

Please elaborate.  I'm not familiar with tetra hop extract or its impact on head formation/retention.

-Cheers

[mtnandy]

Ok, so if the mash schedule isn't critical for the head, is it critical to do a certain rest to drive off DMS? I've never done an all-pils mash, but I've heard something about DMS before. What temp is used for that rest?

[denny]

There is no rest for DMS AFAIK.  DMS is driven off in the boil.

[James Lorden]

I don't do a protein rest, but some people think that it helps with head retention.  I think current opinion of most homebrewers is that to long of a protein rest will actually be detrimental to head retention.  Since you want a low mash temp for that beer anyway I see know problem with doughing in at protein rest temp and immediatly starting to ramp up to 147 if your system is capable of such a task.  In this case you won't be in the protein rest range for very long and if there are any benefits to a short rest you'd see them.  Personally, I've made a Duvel clone before with a single infusion mash and normal hopping regime and still ended up with a rocky head of foam.

[dbeechum]

Please elaborate.  I'm not familiar with tetra hop extract or its impact on head formation/retention.

Sure - Tetra is a CO2 distilled hop extract. The major hop guys all make it. Here's Hopunion's Sale Page for it.

In the brewing world things are talked about being foam positive or negative (say fat and oil for instance). Turns out hops are very foam positive. I forget the chemistry at the moment, but think of any big DIPAs you've had, that sticky foam that hangs out all the way to the end of the glass - that's due to the hops. Tetra does the same thing, but turned up to 11.

[denny]

The other thing to keep in mind is that fermentation practices play a big part in Duvel foam.

[bluesman]

Also...make sure to pitch a calculated amount of clean and healthy yeast into a well aerated wort. As Denny has eluded to...ferment at a STEADY temp in the mid to upper 60's. As the fermentation begins to wind down...slowly increase the ferm temp to 72 over the course of several days. One degree a day as a general rule is appropriate. This will help the beer properly finish.

[hoser]

If my memory serves in Brew Like a Monk Duvel is approx. 82% 5 varieties of Pils and 17+% Sugar.  Mash 146-148F.  Styrian Goldings at 60min and Sazz at 30min.  As Drew says they may be using hop extract now.  Fermentation starts at 61-64F and they let it slowly rise over 5 days to 72-74F.  Well oxygenated/aerated.  I believe Belgian yeast certainly helps with head formation and retention, as do hops.   Looking at the recipe of the week on the AHA homepage, it looks somewhat similar.   Also, WLP570 is the Duvel strain, I believe...

[denny]

Also, WLP570 is the Duvel strain, I believe...

As is WY1338.

[mtnandy]

There is no rest for DMS AFAIK.  DMS is driven off in the boil.

That's what it was. I knew there was something that needed to be done to drive off DMS; I just couldn't remember if it was in the mash or the boil. Do you recommend a 90 min boil for this style?

Also...make sure to pitch a calculated amount of clean and healthy yeast into a well aerated wort. As Denny has eluded to...ferment at a STEADY temp in the mid to upper 60's. As the fermentation begins to wind down...slowly increase the ferm temp to 72 over the course of several days. One degree a day as a general rule is appropriate. This will help the beer properly finish.

I have a 3.5L starter of 1388 going right now.

[denny]

There is no rest for DMS AFAIK.  DMS is driven off in the boil.

That's what it was. I knew there was something that needed to be done to drive off DMS; I just couldn't remember if it was in the mash or the boil. Do you recommend a 90 min boil for this style?

I've never found DMS to be an issue and almost always do a 70 min. boil (10 for the hot break to form, then 60 for the hops) with pils malt.  But doing a 90 min. boil is certainly the safest thing to do.

[James Lorden]

Realistically, if you can chill fast enough DMS should never be a problem even if you do leave some precursor in the pot.  I have used an immersion whirlpool chiller that could get the entire volume to 100 in about 10 minutes and I've used a therminator that allows me to knock out the entire volume to pitching temp in about 10 minutes - never noted DMS in any of my beer.

[tom]

This is a great, short review of DMS:  http://www.picobrewery.com/askarchive/dms.htm

Note that they include a 60 minute whirpool before chilling.