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 Home Brew Forums > Efficiency Calculations in ProMash
04-08-2006, 01:36 AM   #1
RichBrewer
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 Efficiency Calculations in ProMash

I've noticed that ProMash has an efficiency calculator on the recipe side as well as the session side. The problem I have is on the recipe side it says I'll get an OG of 1.060 with the recipe at 75% efficiency. On the session side I will document the brew and I end up with say 1.054 for my OG. The part I don't understand is that it tells me I got 81% efficiency. I'm assuming this is because of the water needed calculations that account for wort loss from the mash tun, brew pot, etc... How do you formulate a recipe in ProMash to get an accurate starting gravity? Do you have to account for wort loss on the recipe side as well?
Am I reading too much into this?

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04-08-2006, 01:46 AM   #2
Baron von BeeGee
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My method: on the recipe side you start with some random figure that seems somewhat reasonable, like 70%. Calculate your ingredients for the OG you wish to achieve at a given batch size. Buy your ingredients, and start a session...

Now, the most accurate time to get an efficiency reading (and we're really talking lauter efficiency here which is what homebrewers are usually talking about) is in the kettle - after lautering, but before boiling. The only loss that needs to be taken into account is the deadspace in your lautertun. You have a volume (such as 7 gallons), and you have a gravity reading (such as 1045 pre-boil). Put this into the efficiency calculation in the brew session (make sure to indicate reading taken in kettle and not in fermentor) and see what you efficiency is.

From this number you can start adjusting the efficiency number on the recipe side so that you don't use too little or too much grist. But it's an iterative process and requires several sessions, at least. I've also found grains matter, at least wheat. I get ~78-80% with all barley recipes, and more like 68-72% with wheat based grists.

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04-08-2006, 02:07 AM   #3
davidkrau
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How do you adjust the grains to get a specific gravity?After I've done my lautering and before the boil I determine the volume with a marked dip stick.I then take the SG and adjust for temp. At that point you can determine the efficiency but it's to late to adjust the the grains at least for that brew. I assume that the adjusting is for future brews. See my current Thread (I'm Confused )in all grain section

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04-08-2006, 02:47 AM   #4
Mudd
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Quote:
 Originally Posted by davidkrau How do you adjust the grains to get a specific gravity?After I've done my lautering and before the boil I determine the volume with a marked dip stick.I then take the SG and adjust for temp. At that point you can determine the efficiency but it's to late to adjust the the grains at least for that brew. I assume that the adjusting is for future brews. See my current Thread (I'm Confused )in all grain section
Basically, Yes.
BUT; if you are lower than expected, you can sparge a little more and boil it off to make your OG.
OR; you can calculate how much DME to add to bring up your OG.

After going thru the iterations /per Baron von BeeGee, you can ajust your grind and grain bill to hit your target gravities pretty reliably.

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04-08-2006, 02:57 AM   #5
RichBrewer
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Quote:
Nice job explaining and thanks!
That makes perfect sense to me. I'm going to try that on my next brew.
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