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Anyone else having their grains crushed at NG and getting really low efficiencies? My last batch had a beersmith estimated OG of 069 and a measured OG (just before pitching) of 042.

Was this a one time thing, or more often? Also, which location are you going to?

The last 2 were quite low. I buy from NG in burnside.

What was your grain bill? The difference between 069 and 042 are huge, more than a shitty crush will give you. However, the crush is one of the largest factors effecting efficiency.

Check this out: http://braukaiser.com/wiki/index.php?ti ... on_mashing

Could your mash temperature be off due to an uncalibrated thermometer? I'm assuming you did a 60 minute mash? Are you 3 vessel or BIAB?

If you are worried get them to double crush next time

Possibly. I just use a mercury thermometer, no real way to calibrate it.

10lb pils, 1lb aromatic, 0.5lb munich, 1lb cane suger, 3-vessel system.
I'm probably doing something wrong; I just wanted to see if anyone else had complaints about NG crushing, just to rule it out. The crush didn't look bad.

I don't have a pH meter yet.

They crushed mine for years, and I usually had fairly good efficiency before I switched to batch sparging. Their mill isn't adjustable either, so I don't think that would be the problem.

I don't have a ph meter either, but based on your recipe and the water here I doubt that would matter much anyway. How are you measuring your volume? Are you leaving a lot of wort behind in the kettle?

Take this with a grain of salt (I do no-sparge) but could you be sparging too fast?

Also, how are you sparging, fly or batch?

What was your final volume like as compared to what you were aiming for? Were you short on volume, or did you have more than expected?

Fly sparged for 35 minutes. Last batch ran a bit short, but this latest batch hit pretty good for final volume; maybe 2 liters left in the kettle (plus the extra 7 liters below the ball valve.)

At this point I think it's my thermometer. I'll pick up a 2nd just to double check things.

Latest batch was a single 150F rest for 60 minutes.

If you're concerned about conversion, you can check a sample with iodine. It takes just a minute and a bottle is cheap (I think) and lasts forever.

You can "calibrate" a mercury thermometer by checking it at boiling and add a piece of masking tape around the thermometer with a correction factor written on it. If it is reading 101C at boiling then write -1 on the tape flag to indicate you need to subtract 1 degree from the reading. We do this all the time in our lab since no thermometer is perfect, although you'd have to be off by quite a bit to get that difference in efficiency during brewing.

Just before Xmas I believe NG Burnside made some repairs to their grinder. I noticed my efficiency went up so I asked the question, since my batches were pretty consistent. I've since gotten a mill so don't know if anything has changed there.

HopGrower wrote:Possibly. I just use a mercury thermometer, no real way to calibrate it.

Stick it in a glass of ice water - fill the glass with ice, top up with cold tap water to fill the spaces. It should read pretty close to 0. Then take a reading in boiling water. Then you will know how far off you're thermometer is at both ends of the scale.