Figuring out efficiency?

[sanders5x]

I've never really cared about efficiency before, I just didn't worry about it. So I was wondering, when I get ready to brew again I would like to figure it out. So whats the easiest way to calculate efficiency?

[Ó Flannagáin]

BeerSmith... if you don't have software to calculate though, just post up your grainbill and the OG you hit and I'll gladly tell you if someone doesn't beat me to it.

[sanders5x]

Ok, I figured it was something that you could hand calculate. I didnt realize you needed some software

[Ó Flannagáin]

Well, you need to calculate the total possible sugars you can pull from your grain bill. Since each grain has a different amount, it tends to be very tedious to calculate without software. Once you have that number it's 100% efficiency, so you just take a ratio of what that OG would be to the actual OG you got... say 100% efficiency was 1.060 and you got 1.050 then your efficiency is whatever the percentage 1.050 is of 1.060 which I would also need a beer calculator for.

[MrMarbleHead]

Got a question, do you guy suse your Pre or Post boil gravity when figuring efficincy?

[Ó Flannagáin]

Post boil always. I check my total post boil volume, which is usually more than what I was shooting for, and change that number in beersmith. Then I adjust the efficiency number in BeerSmith until it changes the OG to the number I read. If you use your preboil number you won't be getting your true efficiency, you'd have to try and calculate how much water you are gonna lose over the course of the bottle and how much that is going to effect your gravity.

[MrMarbleHead]

When i punch my numbers in to Promash it has a space for pre & post boil gravity......ok never mind i just went back to Promash and figured out where i was going wrong....off to smack myself in the head.

[DrunkenSatyr]

You also MUST take into consideration your dead space, i.e. CFC, waste in the MLT, leftover in the pot...... you have to get really exact if you want a true efficiency.