Conversion Efficiency Question

When do I measure the first runnings gravity when measuring conversion efficiency using braukaiser’s method?

Today I collected 4 gallons first runnings. I measured 14 Brix after collecting the entire volume. Was I supposed to measure right after vorlauf (before draining the batch)?

When I calculate conversion efficiency I get 14/17.6 = 79%. I got the 17.6 from a table on the braukaiser site based on my qt/lb mash ratio of 1.7.

My brewhouse efficiency for the same batch was 76% (quite normal for my batches).

Did I calculate the conversion efficiency correctly? If so my lauter efficiency is good but my conversion can go higher.

PS. I batch sparge.

PPS. I average 76% brewhouse so I am not really trying to go higher. I was curious about conversion efficiency because I read you should be getting close to 100%.

Run off your entire mash and take the gravity reading from that.

Since you’re batch sparging, it doesn’t matter. The gravity will only change during the lauter if you’re still converting. What I do is check it at the beginning of vorlaufing so that I know whether I need to extend the mash rest.

Did you check gravity for the second (and higher, if any) runnings? To get 76% overall efficiency with 79% conversion for the first runnings you would almost have to have gotten additional conversion during the sparge(s).

That’s what I did. Thanks!

I didn’t check the gravity of the second runnings by themselves.

Yeah, pretty much so.  I take it from the full runnings just in case.  But, as you point out, at that point it’s too late to do anything but accept it.

Thanks guys. I downloaded a spreadsheet from the braukaiser website. My conversion efficiency was actually 91%. I forgot to add the mash out water volume when calculating the qt/lb ratio.

91% makes more sense.

I am not sure if I should try to improve this or not.

I base my recipes on 95% CE and call it good at anything >90%. That way my OG will never be more than 5% off.

And I can’t believe I forgot to pimp my sparge calculator: Batch Sparging Calculator « SeanTerrill.com

Thanks. Cool calculator.

Thanks Sean, gonna have to put this to use next brew day