Pre-boil volume

Hello all. My question is in regards to a 2.5 gallon batch. Typically what pre-boil volume do you use? The reason I ask is I tried my first 2.5 gal batch yesterday. Pre-boil volume was 3 gals and I only got a little over 1.75 out of it.

 

There was recently an article about understanding water volumes;

http://www.homebrewtalk.com/understanding-brewing-volumes.html

P.S. thats my first link here so I hope it works, the article title was "Understanding Brewing Volumes" if you need to search for it.

 

Pre-boil volume has a lot to do with your specific boil off rate, plus trub volume, plus equipment loss volume. Right now, with what you posted, it appears that your boil off was 1.25 gallons, so in future batches you would have a pre-boil volume of 3.75 gallons.

3.75 pre-boil minus 1.25 boil off = 2.5 gallons of wort.

 

Or you could use some brewing software, or a site like www.Brewtoad.com, or www.BrewersFriend.com This will tell you what your volume should be...

 

Does 1.25 gallon boil off seem like a lot?

 

It depends on the surface area of the pot, how high you have the burner turned up, humidity in the air, etc. As a ballpark I boil off about .75 gal per hr in my 5 gal pot on the stovetop, about 1.7 gal per hr in my 20 gal pot and burner.

 

No, but every system will be a little different. I use an SP10 burner and a 10 gallon SS pot. Mine is fairly wide compared to others I have seen pictured.

I have trouble keeping it lit when turning the gas down low. So I think I may be boiling with a hotter flame than most. I boil 7 gallons to 5 in an hour so 2 gallons per hour.

At to trub and equipment loss, I bag my hops and leave very little in the kettle, so loss is not significant in my boil off rate.

 

Mine is a 5 gallon kettle as well. I use two burners to get it to boil then move it to just one for the hour. Much slower roll.