Kettle Evaporation Rates

[naes100]

Hi everyone, looking for some comments! I am trying to dial in my equipment and just started to use beer smith… I tried to figure out my evaporation rate today.. started with 24 litres… boiled for an hour… ended with 17.5 L or a 27% evaporation rate which seems way high compared to what I see online.

I have a 15 gal kettle I purchase from Ontario Beer Kegs (http://www.ontariobeerkegs.com/15_Gallo ... -2weld.htm" onclick="window.open(this.href);return false;) and I typically leave the cover off when I reach a boil.

Any general comments???

[LeafMan66_67]

My OBK 15G kettle is fairly consistent at 6.67L per hour. My 15g keggle was 6L/hr. Don't worry about percentages.

[jacinthebox]

My 19gal pot with the flame on bust boils off 10L an hour

[spears104]

Evap rate is influenced by diameter. I have a fairly wide home made pot and it boils off 10L per hour.

[naes100]

So I guess 6.5L per hour is ok … appreciate the comments, was making me paranoid! Thanks!

[jason.loxton]

I've never understood evaporation rate given as a percentage. It makes zero sense. For example, a constant 10% boil rate would translate to 1.5 gallons per hour if you've got 15 gallons in your kettle, but only 0.5 gallons an hour if you're boiling 5 gallons in the same pot. That's just not true. Boil off will be relatively constant, and largely determined by surface area/kettle diameter, regardless of how full one's kettle is. Change your Beersmith setting so that boil off is given as a rate per hour in litres/gallons, rather than percent of volume.