Determining Pre Boil SG Target

[acroporabrewer]

I have created a recipe for a rye ale and was wondering how to calculate the pre boil SG target. I understand how to calculate it based on the post boil OG reading but how do you know how much boil off you will have? Can somebody help me estimate this? I am assuming that this is based off of the amount of grain but I cannot find anything. Below is my recipe.


Briess 2-Row Brewer's Malt 11 lbs, 0 oz
Weyermann Rye Malt 2 lbs, 0 oz
Briess 2 Row Caramel 80 0 lbs, 10 oz
Briess Flaked Barley 0 lbs, 8 oz
Crisp Chocolate Malt 0 lbs, 0.125 oz
Columbus Pellets 1 oz @ 60 mins
Chinook Pellets 1 oz @ 60 mins
Chinook Pellets .5 oz @ 30 mins
Chinook Pellets .5 oz @ 5 mins
SAFALE US-05 American Ale 1 ea


OG FG IBU SRM ABV
1.056 - 1.075 1.010 - 1.018 40 - 70 6 - 15 5.50 - 7.50

 

[Hammy71]

Boil off is determined by the pot dimensions and the strengh of the boil. Your boil off should remain pretty constant, however ambient temperature is an other variable. I burn off more on cold days than warm ones (I brew outside). Best practice would be to do a test run with just water. Put 5 gallons in your pot and boil for 15 minutes. Let it cool and measure how much you have left. Take the difference and multiply by 4 and you have your boil off for an hour. If your burn off a 1/2 gallon an hour than you'll simply have to make sure your have 5.5 gallons of runnings in your pot when you start off. After the boil take your SG. If you have 5 gallons and the SG is too high....then your efficiency was higher than expected. If too low, then the opposite. Next brew you'll have to adjust your grain amounts accordingly. It is a trial and error process to nail down your efficiency. No two people will have the same results because there are to many variables between equipment and processes, mash tun design, kettle size, grain crush, etc. Hope that early morning rambling helps....

 

[IL1kebeer]

How many gallons are you collecting at the start of the boil?

What's your efficiency?