Efficiency?

[Bikeworks]

I've got a Smoked Porter in primary and I am wondering about efficiency. Efficiency ratios give you an idea of how much of the starches available in a grain bill are converted to fermentable sugars, right? So if my OG is 1061 and finishes at 1015 what does that tell me about my efficiency of this batch? Or am I thinking about this all wrong? I see recipe logs that calculate strike water amounts and temps. They ask for basic data such as grain bill size and temps, but then they ask for brew house efficiency. How does someone calc that? Do you calculate that, or do you just guess? This is just my second AG batch so...

 

[ncbrewer]

OG and FG tell you about attenuation. Efficiency comes from sugars in the final wort vs theoretically available sugar in the grain. Efficiency can be calculated at a couple of different points also. Braukaiser.com has a good write-up on efficiency - excellent read.