mash efficiency

Does anyone have an easy equation to figure mash efficiency? I brewed my second batch of all grain yesterday. I didn't figure eff. For my first batch, but I wanted to for this batch. I was reading Palmer's how to brew, I might of had one to many by the time I was reading it: ) but I couldn't figure it out.

It's really easy.

Multiply your gravity by your volume to get gravity units.
Gravity Points x Volume = Gravity Units

So say you had 5 gallons of 1.050. 50 x 5 = 250 gravity units

Divide your actual number into the 100% efficiency number. Let's say it's 312.
250/312 = 80% efficiency.

As for the 312...that's determined by your recipe. A good approximation is (Grain weight) x 37. Each grain has a theoretical 100% effieciency extraction, often listed as Points per Pound per Gallon, or PPG. Most base malt is ~37 (meaning 1 pound in 1 gallon gives you 1.037).

Important note: There are a variety of efficiency measures:

• Mash efficiency: How much starch is converted to soluable sugar
• Lauter efficiency: How much of the sugar is extracted versus left stuck in the grain bed
• Brewhouse efficiency: How much of the sugar made it into your fermenter

Thanks. That makes sense. Its all starting to come together now.

Or if your lazy like me, and don't have Beersmith yet....

http://www.brewheads.com/efficiency.php