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malt20 · 11-27-2011, 09:16 PM

my effiency is saying im only getting 51%!
preboil reading is 1.035.
post boil i hit my target og at 1.063.
this has happened to times in a row.
i use a 10 gallon rubbermaid cooler.

recipe was
10.5# pale ale
1# wheat
1# crystal 120
.35# chocolate
.35# carafa.
i was going for a black ipa.
mash at 150 degrees for 65 minutes.

i had 2 gallons mash water
and 5 of sparge water
took reading from 7 gallons wort at 75 degrees.
local brew shop told me no way im getting that low % effiency with a rubbermaid cooler.
so why is my pre boil reading so off yet im hitting my target og?

erikhild59 · 11-27-2011, 09:45 PM

Because you are boiling away water content, thereby concentrating (or reducing, to use a cooking term) your wort. Also, looks like around 13lbs grain mashed in 8 qts strike water. That's about 2/3 qt /lb, which is on the low side. Perhaps a ratio of 1.25 or 1.33 qt/lb would help. Just my two cents.

hercher · 11-27-2011, 09:48 PM

Right off the top, I don't think you have nearly enough mash water. You should figure 1.25 quarts per pound of grain. so with that grain bill, you should be using 4.125 gallons of water.

You also don't mention what your sparge technique is -- batch sparging or fly sparging. I fly sparge, and have recently learned that slow is the way to go. I nearly doubled my run-off time from 23 timutes to 41 minutes, and all other steps the same, increased my efficiency from 68% to 79%.

See another thread I started and got some really good advice for other suggestions.

http://www.homebrewtalk.com/f13/efficiency-questions-272264/

There is also this thread, which has a ridiculous amount of good information: http://www.homebrewtalk.com/f36/attention-new-all-grain-brewers-30466/

Lastly, you hit your target, so relax, don't worry, have a home brew.

erikhild59 · 11-27-2011, 09:52 PM

Quote:

Originally Posted by hercher

right off the top, i don't think you have nearly enough mash water. You should figure 1.25 quarts per pound of grain. So with that grain bill, you should be using 4.125 gallons of water.

Second, at what temperature are you taking your gravity readings? Your hydrometer is calibrated to be accurate at 60 degrees f. For every 10 degrees over that, you should add .002 or .003. So if your pre-boil reading was at, say 140, then it really is somewhere in the range of 1.053 - 1.059.

You also don't mention what your sparge technique is -- batch sparging or fly sparging. I fly sparge, and have recently learned that slow is the way to go. I nearly doubled my run-off time from 23 timutes to 41 minutes, and all other steps the same, increased my efficiency from 68% to 79%.

See another thread i started and got some really good advice for other suggestions.

http://www.homebrewtalk.com/f13/efficiency-questions-272264/

there is also this thread, which has a ridiculous amount of good information: http://www.homebrewtalk.com/f36/attention-new-all-grain-brewers-30466/

lastly, you hit your target, so relax, don't worry, have a home brew.

+1

malt20 · 11-27-2011, 10:12 PM

im batch sparging. so do i take my pre boil reading after i collect the wort from the mash and not from the sparge? i was trying to use less mash water and have a really thick mash. (Read in a boot to do this for ipa's and pale ales)

malt20 · 11-27-2011, 10:14 PM

i went from 7 gallons pre boil to 5 gallons post boil in fermentor. boil time about 70 minutes

**ajf** · 11-27-2011, 10:21 PM

I agree about insufficient mash water. You need between 1 and 2 qts per lb grain, and 1.25 qt is a good starting place.
You say you used 2 gallons strike water and 5 gallons of sparge water, then you say you took the pre-boil gravity from 7 gallons wort.
With 13.2 lbs grain, you will lose about 1.5 gallons to grain absorption, so you will only have about 5.5 gallons of wort (unless you topped off with water after the sparge).
If you really had 7 gallons of wort at 1.035, and you ended up with an OG of 1.063, you would end up with < 4 gallons into the fermenter. Perhaps you ended up with a short volume, or perhaps you didn't mix the wort sufficiently before taking the pre-boil volume, or perhaps you didn't cool the wort to the hydrometer calibration temperature before taking the reading. All of these would introduce errors into your calculations.

-a.

malt20 · 11-27-2011, 10:32 PM

i ment i got 2 gallons from the mash. my bad. i used 1 quart per lbs of grain. so like 3.25 gallons in mash, then collected 2 gallons. just wish i could pin point my effiency. i reversed the calculations and if i do it this way my eff% is 67%

malt20 · 11-27-2011, 10:34 PM

just dont know why its only 35gu pre boil

**ajf** · 11-27-2011, 10:46 PM

Lack of mixing of the wort prior to taking the sample. If you batch sparge, your first runnings will have the highest gravity, and they will be sitting on the bottom of the kettle. Your sparge runnings will have a lower gravity and will sit on the top of the kettle. If you collect your gravity sample from the top, it will have a low gravity. If you collect from the bottom, it will have a high gravity. If you mix the wort thoroughly before taking the sample, you will get a correct gravity.
Same thing applies to fly sparging, but to an even greater degree.

-a.