Efficiency, after mash or after boil, does it matter?

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Todd

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I'm trying to get an idea of how efficient my setup is. I don't have an exact measure of the post sparge volume and I forgot to get a hydrometer reading. I did do it after the boil. It came out to 68%, is this not a valid measure? The reason I want to know if for changine recipes and such so I know how much to change the grain bill.

Any ideas?

Also I'm getting about a half gallon of water absorbtion per pound of grain, is there anyway to reduce it? Is that normal?

Todd
 
AFAIK, efficiency readings are taken from the final volume of wort. As such, the hydro measurement should be taken just prior to pitching.

I think the water retention is normal. You can extract more by pressing on the wort with the bottom of a pot or bowl if you want.
 
You're losing half a gallon per pound of grain? Is that right?

Most people figure more like .1 gallon lost per pound of grain. (I think I lose about .15).

So if you put a total of 9 gallons of water and 10 lbs of grain into your mash tun, you are only getting 4 gallons of wort out?

As far as efficiency pre- or post-boil, it doesn't matter. It's the same amount of sugars in the wort--all that's different is how much water its suspended in. The efficiency will be the same.
 
cweston said:
You're losing half a gallon per pound of grain? Is that right?

Most people figure more like .1 gallon lost per pound of grain. (I think I lose about .15).

So if you put a total of 9 gallons of water and 10 lbs of grain into your mash tun, you are only getting 4 gallons of wort out?

As far as efficiency pre- or post-boil, it doesn't matter. It's the same amount of sugars in the wort--all that's different is how much water its suspended in. The efficiency will be the same.
Click to expand...

sorry, half a quart per pound. I normally lose about 2 gallons on a 1.060 beer. I have a big mash tun with a thin grain bed could that be contributing to it?
 
I would think that efficiency would be measured by the final gravity before pitching. It seems to be the true measurement.
My absorbtion is about .13-.15 quart per pound. A 1\2 gallon seems really high.
 
Todd said:
sorry, half a quart per pound. I normally lose about 2 gallons on a 1.060 beer. I have a big mash tun with a thin grain bed could that be contributing to it?
Click to expand...

Sorry--I could have probably figured that out.

half a quart is .125 gallons. That's right in the usual range of liquid loss.
 
Blender said:
I would think that efficiency would be measured by the final gravity before pitching. It seems to be the true measurement.
My absorbtion is about .13-.15 quart per pound. A 1\2 gallon seems really high.
Click to expand...

Gravity potential in grains is expressed in gravity points per pound per gallon. If your grain bill is 10 lbs of grain with potential (at theoretical 100% efficiency) of 370 points, then...

for a five gallon batch, the gravity would be 1.074 at 100% efficiency. At a more reasonable 75%, it'd be (370 * .75) / 5 = 55.5 (i.e. 1.0555)

If you took a reading after collecting the 7.5 gals of wort at 1.037, then that's the exact same number of gravity points...

(370 * .75) / 7.5 = 37 (i.e. 1.037)

I think pre-boil is a better time to take a hydrometer reading, because at that point you can still do something about it if it is off (add DME, increase or decrease final batch volume, whatever.)
 
cweston said:
Gravity potential in grains is expressed in gravity points per pound per gallon. If your grain bill is 10 lbs of grain with potential (at theoretical 100% efficiency) of 370 points, then...

for a five gallon batch, the gravity would be 1.074 at 100% efficiency. At a more reasonable 75%, it'd be (370 * .75) / 5 = 55.5 (i.e. 1.0555)

If you took a reading after collecting the 7.5 gals of wort at 1.037, then that's the exact same number of gravity points...

(370 * .75) / 7.5 = 37 (i.e. 1.037)

I think pre-boil is a better time to take a hydrometer reading, because at that point you can still do something about it if it is off (add DME, increase or decrease final batch volume, whatever.)
Click to expand...
I do both readings and your point is well taken. I suppose that what I try to strive for is an overall efficiency and that is why I prefer the pre pitch reading.
 
I do both as well. 1 for pre-boil to check efficency and one prior to pitch for OG / FG % alc. When I'd check efficiency from the pre and the post boil I always got higher points on the post. Probably incorrect measurement of volume I s'pose. I think you stick with one and it tells your story personally.
 
Evan! said:
AFAIK, efficiency readings are taken from the final volume of wort. As such, the hydro measurement should be taken just prior to pitching.

I think the water retention is normal. You can extract more by pressing on the wort with the bottom of a pot or bowl if you want.
Click to expand...

I wouldn't do this with any force. Sounds like a great way to extract tannins from the grain bed. For similar reasons, you should not squeeze the grain bag when steeping specialty grains.

BTW, efficiency is a measure of your entire process, so you could do it pre or post boil - just change the total volume of wort in your equation or in Promash.
 
Thanks guys. Since I'm batch sparging I generally just end up with what I end up with. I was pleased to find on this last beer I actually did better than the recipe.
 
I take two reading.

One Pre Boil and one at the fermenter.

The first gives me my mash/extraction efficiency and the latter my "Brew house efficiency
The difference in the two are down to to vigorous a boil driving off some sugar and dead space losses.
I want to know both.
 

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