Why are 60 and 90 minute boils the norm? Why not longer?

I brewed a Hefe today following some advice Eric Warner gives in his book on the style. One of his tips is to boil for 120min. I got a lot more hot and cold break with the 120min boil than I usually do with a 90min boil. Is there a reason I shouldn’t boil all my worts for 120min?

Energy consumption? Obvious, but worth considering…

i have pondered this too. i have boiled 90 minutes but never longer.  i have seen a few people advocate shorter boils.  i have never read any “must boil xxx”

I think there are a few reasons.  First is wort darking and caramelization.  The second is that the isomerization activity of alpha acids plateau’s completely by 90 minutes.  Third is that the benefit of SMM volatilization drops off appreciably as the malt’s reserve of SMM is relatively exhausted around 60 minutes for pale malt and 90 minutes for pils malt.

Yeah, 90 minutes to drive off SMM for pils malt, 60 minute should be fine for all other styles, though I always boil at least 90 min. I have read that boiling too long can degrade head retention. On higher gravity beers I normally boil for closer to 2 hours to boil down to my OG.

Martin - It sounds like it’s not strictly necessary, but I’m wondering if there are any ill-effects (other than unintended caramelization). As Keith pointed out, maybe head retention would be an issue? I’ll let you know if I notice any head retention issues next month when it’s bottled and carbed.

I believe Pilsner Urquell used to boil for 120 minutes.

At one time read that they did longer than that, but it was a weak boil, more of a simmer.

I’ve done some loooong boils up to 5 hours to boil down a Barleywine. Anyway I used to follow convention and boil for 90 minutes for all my malt bills.

I backed off on that and do a max of 60 now.  Once the boil is attained I let it go for 15 minutes and then add my bittering charge at a max of 45 minutes.

I look for a good break before any hops are added. Pilsner malt will produce a nice eggy break like egg drop soup and basic 2-row not as much.

:o

I’ve been boiling everything for 60 minutes, mainly because of brew-time constraints on the weekend.  However I make sure it’s a very vigorous, rolling boil.  Will this suffice for Pils malt or is 90 minutes the rule, period?

I’ve never actually had any flavor issues with pils malt and a 60 minute boil, but lately I’ve been going for at least 75 minutes with bittering hops added at 60.

If you chill quickly you run minimal risk of DMS formation.  I also think the levels of SMM may vary somewhat between malts depending on the exact kilning regimen and 90min is safe for the upper end.

I probably end up closer to 75 mintes as I wait for a solid hot break before adding my first bittering addition of hops.  My IC has the wort below 70F in 15-20 minutes depending upon the season.

I have two lagers fermenting right now and plan a 3rd this weekend with Floor Malted BoPils.  If I need to bump it up to 90 minutes I will, but want to make sure it’s a necessity.

Dave

What it all boils down to is wait for the wort to foam up and drop back into itself. That’s the hot break. I won’t add hops until then. Boiling purposefully longer than that isn’t necessary IMO. Unless you have a specific reason like a boil-down like I did with the BW. That was a triple sparge and a large grain-bill and would have produced 20 gallons of regular beer.

I’ll use a long boil (120 min+) if I want to hit a gravity number or volume, or if I want to increase complexity via kettle caramelization (scottish, BW). I havn’t really worked with pils malt much but a 90 min doesn’t seem unreasonable.

Martin and Keith hit it on the head - 60-90 min boil will give you all the isomerization and SMM volitization that you need - ASSUMING you keep a good, rolling boil throughout.

Urquell probably had a longer boil because of an inefficient kettle OR because using a hard boil would create hot spots and darken the wort.

At home, if you’ve got a good, stainless or dense aluminum brewpot and adjust your air/gas valves for an efficient burn, a good, rolling boil without hotspots is easy to maintain. In fact, most homebrewers have to cut back on the boil intensity. (Martin actually pointed out to me that I was “boiling the Be-Jesus” out of a Saison at a Big Brew a few years ago - has since been corrected)

If you use a long boil to concentrate or carmelize wort, add the bittering hops no earlier than the 90-mark. I think hops (much like over-cooked vegetables) have a dull, papery, “vegetal” flavor.

I think it is worth playing with, but I always do at least a 90 min boil with pils malt.  It really depends on your palate (and if you are entering competitions, the judges’ palates).

This is your weekly reminder that caramelization can’t happen in wort under atmospheric pressure, and that the term is “non-enzymatic browning”. Now back to your regularly scheduled thread. ;D

+1.  I was dying to say that, but I say it so often that I was waiting for someone else to mention it!