Why such low effeciency?

[Unferth]

Hi all,

I've done about 7 partial-mashes and my effeciency has been, until last night, pretty decent. around 60-80%. Last night, as best I can figure, the effeciency was below 20%.

Any suggestions or comments are most welcome.

Here's what I did:

Grain bill:

3.5 # 2 row.
5 oz crystal malt
4 oz wheat malt
8 oz barley flakes
1 oz Roast Barley
(+ 4lbs LME and .5 lbs Dextrose)

Step one, the mini-mash:
I heated 2 gallons of water to 162f, and added my grain (in a bag).

The temp dropped to 152 (right on target), I wrapped mash tun in towels and put in the oven (pre-heated to about 150), turned off oven and let it sit for 1hr, 15 m.

when I got the wort out the temp had dropped to 149.

Step two: sparge.

I let the grain drain into the mash tun through a strainer, and sparged with about 1 gallon water at 170F. (meaning I poured it over the grains and let it drain)

Step three: boil.

nothing unusual. I added the 4# LME at flameout along with the .5 # dextrose.

Step 4: cool and test gravity.

I cooled the wort to about 75, topped up to 5.5 gallons, and checked the gravity.

It was at 1.032.

I estimated, with a low-ball 60% effeciency, to get 1.050 or there-abouts.

WTF? I had a long mash at a reasonably consistent low temperature. If anything, it should be higher this time.

Any ideas?

 

[BBL_Brewer]

I have no idea where you went wrong. By my calculations (with a 60% efficiency) you should have had an OG in the low 1.060's. The LME and Dextrose alone would put you at around 1.030 into 5.5 gallons. Are you sure you took good readings? Maybe your hydrometer is out of whack. You should have gotten quite a bit of sugar from the mash even if it was a low efficiency. I think your OG was higher than you think, and you have a calculation error somewhere.

 

[eluterio]

I would recalibrate your hydrometer just to make sure. The other problem could be that it wasnt mixed well when you added the top off water.

 

[Unferth]

I just rechecked (with the same hydrometer) and the reading is the same. 1.032

I've been using the same hydrometer for a while, and if it is off, this would be a first.

Actually, this is the longest I've had a hydrometer without breaking it.

I didn't check the gravity right of the mash, but it looked and smelled good and the temps were reading as expected, so I didn't feel the need to.

 

[Unferth]

I would recalibrate your hydrometer just to make sure. The other problem could be that it wasnt mixed well when you added the top off water.

I'm not sure I understand you. You mean its possible the wort wasn't mixed with the top up water so it threw off my reading?

I'll stir the piss out of it again and recheck. I'll also check something else with the hydrometer.

 

[Unferth]

my hydrometer measures 60f tap water at 1.00
and my dry red wine at .990. last I checked the wine was in the .995 range, so it's lower than expected, but not .3 points low for sure.

I think the hydrometer is more or less on target.

That would have made sense, though.

Any other ideas?

 

[eluterio]

I've done this when I used to do extracts I had two reading that didn't match up and it was because the wort didn't mix well with the water. With that said did you calculate what your OG would be with the use of top off water?

Hydrometer scan be thrown off after a while. When I bought one it was spot on at 60 degrees then after awhile it dropped 6 points. I have another one that dropped 4.




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[Hopper5000]

How was the grain crush? That can for sure impact efficiency. Even with a low sparging amount you should be getting above 20%. Is it possible for you to sparge more?

 

[Unferth]

LHBS crushed the grain, as normal. I'm not sure the ratio. Never had any other problems out of them.

If the hydrometer is reading normal at 60f, shouldn't it still be good?

 

[BBL_Brewer]

Even at 20% mash efficiency he would have been close to 1.040. Unless the LME was on the low side of PPG. I figured 34 PPG for the LME and ~48 PPG for the dextrose.

 

[Unferth]

Maybe bad 2-row?

maybe the oven was hotter than I thought? even if it was at 170, I should have gotten something out of the grain.

 

[Hopper5000]

Yeah it's possible that the 2-row was bad or old. Do you know what company? I have heard of people having problems with Great Western before. Did the crush appear to be any different than before? Sometimes LHBS change the mill settings.

 

[Unferth]

grain crush was normal. I don't think they've changed anything in 10 years or so.

The malt was Gambrinus. They are from BC, I think.

 

[Hopper5000]

seems like this one might be a mystery then, if it happens on your next brew then it probably will be an issue. As for now, you are gonna have a nice lawn mover beer

 

[BBL_Brewer]

Well, if you know your hydrometer is ok and you're confident about your volumes, then I guess poor conversion could explain the lack of sugar. Starches are not very water soluble. If your grain was old or your mash temp was way off, you could have had poor conversion. You could do a starch test on the wort to check for conversion. If your enzymes were dead, you should have some starch in the wort. Take a small sample and put a drop or two of iodine (iodophor sanitizer works great) in the wort. If it turns black, it's got starch in it. If it doesn't turn black, the starches converted and you can rule that out as the culprit. Just don't confuse the strong red color of the iodine for a positive black result.

 

[Unferth]

That's pretty fancy thinking there BBL.

Generally, I would consider that beyond my simple-brewer philosophy. but I'm determined to find out what's up.

I'll grab some iodine at the store today.

 

[BBL_Brewer]

That's pretty fancy thinking there BBL.

Generally, I would consider that beyond my simple-brewer philosophy. but I'm determined to find out what's up.

I'll grab some iodine at the store today.

Doing a conversion check is not uncommon. Most of us just don't do it very often unless we have a need to. I do one once in a while myself if I screw up and mash too high. I always have iodophor around so It's not a big deal.

 

[eluterio]

I agree with iodine. Had some questionable mash temp and this helps put my mind at ease.


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[Unferth]

So, if I already got pissed off and pitched the yeast last night, the iodophors will still work, right? Yeast won't affect starch...

 

[Hopper5000]

Correct, the yeast won't affect the starch as they can't eat it. This starch can contribute to chill haze too so it's probably still floating in solution. If you wanted to make extra sure maybe rouse everything up and then take a sample.