Surface Area is important for my maple syrup making friends in the club, as the pans are open. Partially closed systems, like a breweries brew kettle with a small diameter stack will be Martin’s case.
I once saw the evap rate a homebreeer from Edmonton got in the winter outside it was crazy high as the relative humidity was very low.
This would apply for the maple syrup pan.
I have always boiled at what I would call a high simmer, nothing violent, but some occasional rolling activity. It matches the videos I think I have seen Martin reference.
If nothing else the reduced energy consumption for the “low boil” vs “volcano boil” is a practical reason alone to reduce the boil. Josh Wiekert presented at NHC that the induction cooktop compared to propane is comparing pennies to dollars. Then from 3.5kw (volcano) to 2kw (low boil) is another 43% less energy.
Technically it makes sense and practically it makes sense.
I’m w/jeffy and BigMonk on the vigor of the boil. I was losing a lot in my initial batches (5-gal. recipes, typically 3-gal. boil) using a high-rolling boil. It occurred to me that if the wort is 212º at an easy boil, the job is getting done and I’m not losing as much volume. I check my level at the tail end of the boil and add (distilled) water to the 3-gal. mark. Not very scientific, granted. I’m thinking of buying an immersion chiller, so might have to shift to measuring the loss after a non-wort 3-gal. boil and adding that volume to my pre-boil volume since displacement would make it impossible to measure the finish. I once made the (apparent) mistake of adding water to the cooled wort in my fermentation bucket to bring it up to the 5-gal. mark. Ended up tasting thin, so I figured that was the problem.
The text and figures for a Zymurgy article on Wort Boiling was handed in last month and it should appear in an issue this summer. The bottom line is that brewers don’t necessarily need to boil long or hard to make great beer.