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

you have each earned 5 pedant points, collect 999,995 more to win this handsome tie pin. Okay, so I use a long boil to acheive greater malt complexity via ‘non-enzymatic browning’. sure tastes like caramelization.

You can get some carmelization with direct fired kettles. Here’s a quote from Brewing Science and Practice:

“Local overheating, as was common with older, direct-fired coppers, can also cause burn-on and carmelization of wort sugars and copper adjuncts…”

Can it be done with SS or aluminum kettles? Not sure with SS, but seems possible with aluminum.

If I find little spots of burnt wort at the bottom of my kettle (because of hot spots) could I reasonably assume it caramelized before it burned? It’s an aluminum pot, and I’ll typically find a couple spots about as big as a quarter that are burnt.

Years ago I was finding some “spots” that I had scrub off. They weren’t burnt but it was obvious to me the heat was too high.

If you are getting burnt spots in you kettle back off on your flame a bit. You’ll still have a great boil. Don’t worry.

The pro-brewer/scientific literature I’ve seen indicates that AA utilization peaks at ~2 hours, but a 90 minute boil is generally good enough. A 2-hour boil might be needed if you’re really trying to pull every alpha acid molecule you can out of the beer in a high gravity wort.

Other than that, spot on.

Big pro-brewers hate long boils both because of energy costs and because time is money - especially for big brewers which might be brewing 4-5 batches per day. They have all sorts of tricks to minimize energy usage and speed up wort boiling. One of the coolest, but trickiest, is brewing the beer under a slight pressurization. AA Isomeration is optimized at something like 215-220 *F, but the danger is that if you get your wort much hotter than that, AA start to degrade :open_mouth:

I look forward to seeing that data.  The isomerization test results from Malowicki and Shellhammer indicate that 90 minutes is the peak.  They found a very slight drop off at 120 minutes.  They also looked at pressurized boiling and established a correlation to energy input and isomerization rate.

I always wait until I actually see hot break in the kettle (egg drop soup). My understanding is you want those proteins to coagulate before you add the hops.

In Warner’s Wheat book, he actually says to add half the bittering hops at -120min and half at -60min, IIRC. The hop bits help coagulate the proteins to provide better hot break.

FWIW the weizen I brewed with a 120min boil, while noticeably clearer going into the fermentor, was not clear in the bottle.

I didn’t peruse the entire thread, but if it hasn’t been mentioned, somewhere around 2 hours into a boil you run the risk of redissolving the hot break. That may be a good thing for long-aged brews like the big Scottish beers, but in general it seems like fodder for infection.

The short answer…because in most cases you simply don’t need to.

Al, you get today’s Gold Star for Pragmatism!

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I feel like the gold star for pragmatism isn’t very pragmatic.

A top hat and cane is a little overdoing it, isn’t it?

Thanks, Denny…I’d like to thank the Academy for this award…
;D