Ideal boil-off?

[erykmynn]

Recently I had a heating device fail at boil, leaving me with a very watery hefeweizen. Then yesterday I mistakenly turned the heat to the wrong setting on another beer.

Which all leaves me wondering....

Is there an ideal rate of boil-off, or perceived boil vigor? Are there effects of flavor? More caramels? Less DMS? Mineral concentration?

I'm very curious if anyone has gotten scientific with this.

p.s. I posted here because I'm almost exclusively AG brewing. I also figured the affects could be a little different with extract.

 

[maida7]

from what I understand the boil needs to turn the liquid over in the pot. It does not need to leap up and down like fountain but it should not have a smooth still surface.

 

[erykmynn]

from what I understand the boil needs to turn the liquid over in the pot. It does not need to leap up and down like fountain but it should not have a smooth still surface.

Gotcha. Definately the one I did with just the stove wasn't really turning over, and since I was expecting a certain boil-off on mash, the beer is noticabl weak, and might have a slight tinge of DMS in the aroma, but not really on the palate.

I was wondering more if anyone had noticed variations in flavor effects at different levels, with the malts, or perhaps in boiling off hops compounds...

What kind of boil-off does a 100+ barrel 'microbrewery' shoot for?

 

[maida7]

Gotcha. Definately the one I did with just the stove wasn't really turning over, and since I was expecting a certain boil-off on mash, the beer is noticabl weak, and might have a slight tinge of DMS in the aroma, but not really on the palate.

I was wondering more if anyone had noticed variations in flavor effects at different levels, with the malts, or perhaps in boiling off hops compounds...

What kind of boil-off does a 100+ barrel 'microbrewery' shoot for?

One important function of the boil is to drive off nasty flavor compounds (DMS).

A "soft" boil may leave your beer tasting like creamed corn, sulfur or cooked vegetables.

A hard boil will caramelize some of the sugars and can leave a caramel taste in the beer. A hard boil also wastes energy.

Both are considered a defect in most styles of beer.

Modern brewing equipment goes to great lengths to drive off those nasty flavors without caramelizing the wort and do it all with the least amount of energy. Steam jacketed kettles VS direct fire. China hats, wort waterfalls, etc...

 

[HarkinBanks]

For our typical 5.5 to 5 g finished batches, I think 1 gal per hour is the perfect number. It works really well in my 8 gal and 10 gal BKs getting me a good boil and a good increase in gravity.