How much evaporation to account for?

[mdstrobe]

I'm using BeerAlchemy and I'm trying to gauge what my pre-boil volume will be. How much water can I account for to evaporate during a 60 minute boil / 90 minute boil?

I heard that you can estimate at .75 gal evaporation for a 90 minute boil, does this sound right?

 

[dzlater]

It all depends
put a measured amount of water in your pot
boil it for a set amount of time measure it again
and then you will know

 

[WrongCoastBrewery]

I typically lose half a gallon in my three gallon boils. But that all depends on the pot, your stove, ect. My stove has a hard time doing a three gallon boil so I might be losing less than someone who uses a gas burner or such.

 

[Yooper]

It depends on several factors- the strength of the boil, the width of the pot, the humidity where you live. I think 1 gallon an hour is a reasonable place to start. It seems like .75 gallons per 90 minutes would be a very low estimate.

 

[hammer1]

i start off with 9.5 to get 8 gallons for a 60 min boil