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On the "Belgian Blond Ale" episode of the Jamil Show (podcast) it was said that you should do a 90-minute boil because of the pilsner malt.

Can someone explain this further?

1 Answer 1

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The reason for the prolonged boil is to drive off the volatile chemical DMS (Dimethyl Sulfide). DMS give beer that cooked corn flavor and aroma. DMS is created as the wort increases above 140ºF (60ºC) from the precursor molecule SMM(S-methyl-methionine).

All base malts have some SMM, but during the kilning process post malting it is driven off. However Pilsner malt is kilned very gently at lower temps to get that low Lovibond/SRM rating. So more of the DMS precursor remains in the malt. The longer boil time ensures that most of the DMS created is boiled off as vapor. Its the reason why you aren't supposed to boil with a lid on; because the DMS condenses on the lid and falls back in the pot.

Pro brew kettles often have a mixing feature that helps drive off the DMS even faster and more efficiently due to the size of the kettles.

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    This. If you have a good rolling boil you can probably get away with 60-70 minutes, but it doesn't hurt to play it safe :-) It's also important to cool the wort quickly, as DMS is produced above a certain temperature threshold, and only evaporates when the wort is boiling.
    – arnemart
    Commented Nov 26, 2010 at 7:46
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    No, with Pilsner malt you really do need 90 minutes with a rolling boil. As brewchez said, it has far more DMS precursor than a regular 2-row.
    – sgwill
    Commented Nov 26, 2010 at 13:46
  • I agree you probably can get away with a 60 minute boil if its really aggressive. Far more aggressive than with my normal boil. And if you boil that hard, would might likely darken the delicate pilsner wort more than you want right?
    – brewchez
    Commented Nov 26, 2010 at 15:22
  • This is great info to have! It's interesting that John Palmer's How to Brew doesn't seem to mention this. He's got recipes in there using all pilsner malt and, unless I've missed something, he just specifies a 60-minute boil.
    – Jeff Roe
    Commented Nov 26, 2010 at 16:29
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    Would the same apply if you are using Pilsner Malt Extract? Maybe a silly question, but I'm still a learner... EDIT: nm, just found answer elsewhere, the answer is NO, it does not apply to malt exract. Commented Mar 7, 2011 at 16:58

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