Just a nit... it's not the precursor (SMM) that's driven off, it's the actual DMS. The heat converts the (non-volatile) precursor to (volatile) DMS, which then boils off.Longer boils are traditional for Pilsner malt heavy recipes, traditionally thought to drive off the increased DMS (canned corn) precursors that Pilsner malt has over std 2-row or 6-row malt.
Squeeze in an extra beer in that thirty minutes as well.It does a couple of things, primarily reducing water, increasing SG. Longer boils are traditional for Pilsner malt heavy recipes, traditionally thought to drive off the increased DMS (canned corn) precursors that Pilsner malt has over std 2-row or 6-row malt. Also, 90m boils are good for getting more maillard reactions and makes porters/stouts richer.
You could certainly reduce that to 60 minutes. Keep in mind that a shorter boil means using less total water and therefore having a lower mash efficiency (compared to what it would have been with more water in the mash/sparge), thus needing a larger grain bill.I found an American Wheat recipe that calls for 90 minutes, does that make sense? 20% of the grain bill is Pilsner.
If the recipe is from a source you trust, consider following the recipe the first time you brew it.I found an American Wheat recipe that calls for 90 minutes
FWIW, I have a couple of dark / malt forward recipes where I played with boil time. For my taste, longer boils for these recipes resulted in more enjoyable beer.Also, 90m boils are good for getting more maillard reactions and makes porters/stouts richer.
It's actually clorophenols and since they have boiling points that lie around 200°C I doubt you'll be able to boil them off unless you're boiling in an autoclave at an extremely high pressure/temperature combination.It also boils off polyphenols which can give a band-aid sort of taste to the beer.
A 90 minute prescribed boil time could simply be an efficiency thing.
Gathering up more sparged wort and all then boiling the heck out of it to hit the numbers...
Just one pedantic nit...The length of the boil is an issue to ensure sufficient time to volatilize the SMM and sufficient movement of the wort to get the volatilized SMM driven out of the wort.
You won't find mention of 90-minute boils in any pro brewing book (well, not anything that was published after 1960 or thereabouts) so I'm guessing you might have got it backwards. The recommendation probably originated from pioneer homebrewers having inadequate systems that barely brought the wort to a boil, ending in poor hot break and possibly DMS off-flavors.A lot of homebrewing lore began by taking advice from pro brewers or pro brewing books without modification for our smaller size and evolution of the ingredients available. One of those subjects is that pilsner malt requires a ninety minute boil to boil out SMM to prevent DMS.