[tommymorris]

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%.

[denny]

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

[a10t2]

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).

[tommymorris]

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

That's what I did. Thanks!

[tommymorris]

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).

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

[denny]

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).

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.

[tommymorris]

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.

[a10t2]

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: http://seanterrill.com/2013/10/05/batch-sparging-calculator/

[tommymorris]

Thanks. Cool calculator.

[69franx]

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


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