AG Yield and Efficiency

[jimbodini2000]

I've just completed kegging of my third ever AG batch and really love AG brewing. Each batch has been excellent and some of the best batches I've brewed in ten years of home brewing. The issue I keep encountering is I'm getting a yield of 3-4 gallons for a 5-gallon recipe. I'm using the Northern Brewer suggested equations for mash water (1.25 qts * # of lbs) and sparge water (2 qts * # of lbs). With each batch, I'm getting ~8 gallons of wort, with sparge water left over. I've stopped sparging each time because I've been worried I was collecting too much. Sure enough, each time my OG has been too low for target and I've had to boil off for as long as 2 hours to get down to a better OG from which to start the hop additions and flameout after an hour. Once I boil off, my efficiency is pretty good (33.25 pts/pound 2nd batch, 25.26 pts/pound using John Palmer's equations), however, between the boil losses, primary fermentation and secondary fermentation losses I'm down to only 3-4 gallons to keg. I think part of the problem is the AG kit I bought from Northern Brewer is the 5 gallon size, so my mash tun is really too small for 5 gallon batches if you account for the space taken up by the grain in the tun. Am I missing anything else?

 

[hophop]

What's your boil off rate for a 60 minute boil? I loose about 1 gallon, so plan on having 6 gallons preboil volume for a 5 gallon batch. I also check my preboil gravity and make sure I'm close to where it needs to be. I wouldn't make 8 gallons of wort if I know I'm going to spend 2 hours reducing it. Just use less sparge water.

 

[jimbodini2000]

My boil off rate is usually around 1 - 1.5 gallons. Thanks for the tip.

 

[grathan]

You could post a picture of your mash tun setup and describe your lautering process in a better detail.