low OG question

[jsmurphy]

I brewed a dunkleweizen last night and according to my recipe I missed my OG by a lot. It says my OG should have been 1.056, and mine was 1.042, factoring in temperature of the wort. But here's my confusion: The recipe called for 5 lbs. wheat DME, and some specialty grains which are steeped, so the only real fermentables were in the DME. According to my calculations, I would have needed almost 8 lbs. of DME, assuming an extract efficency of 80%, or 37 ppg. When I calculate with my 5 lbs. of DME I get an OG of about 1.037, which is close to where I came out.

Is my recipe wrong, or did I screw up get a very low yield somehow?

[sallad]

is it possible that the recipe was for 4 or maybe even 3 gallons?

[jsmurphy]

No, it was 5 gal. I think I'll call my shop where I got the recipe, but I'm not going to stress about it. It'll either be good or not.

[jsmurphy]

OK so here's the deal. My shop guy faxed me the recipe, and it lists the gravity of each grain on the grain bill. Apparently I should have gotten an additional .11 of gravity from the mash. The gravity for the 5 lbs. of DME is listed at 1.045, so I'm close there. So I guess I didn't get any fermentables from the mash, but I don't know why. Here's the mash sequence: Mash w/ 5 qts. water 170*, ph 5.2 for 45 mins. Sparge w/ 5 qts. water 170*, ph 5.8. I don't take ph measurements so maybe that had something to do with it.

Any ideas?

Like I said, I'm not going to sweat it. I'll just have a slightly lighter brew.

[Fast_Eddy]

170F is too high of a mash temp. It will lead to a less fermentable wort. Mash temps should be in the 155F range.

[jsmurphy]

Thanks Fast_Eddy. I'll talk to my local guy about that.

Also, I'm an idiot. I just remembered that I topped off my primary with a gallon of water and immediately took my sample. I'm sure I got a diluted sample. I'm probably a little bit closer to target OG than I think.

Note to self: Limit homebrew consumption when in the process of brewing your next batch...:p

[ray m]

That'll do it, JS....when I extract brewed, I always had to top off. I also made DAMN sure that I shook the living hell out of the carboy to make sure all was mixed together well before taking a reading. I think you're OK:)

[bigmf]

You know, another possiblity exists. Up here in Canada we brew 5 Imperial gallons at a time. 5 imp. gal. = 23 litres. 5 U.S. gallons = 19.5 litres. I have to convert U.S. recipes all the time to get close to the listed original gravities.

My first attempt at a home brew recipe from Papazian's book ended up a fair bit lighter than intended. :rolleyes:

Its probably not the case but I wanted to bring it up so you could rule it out.

M.

[Jughead]

I had the same problem with the US to Imperial Gallon conversion. I was making 23 litre batches from 19 litre recipes. Once I figured out the problem, my extration efficiency went up nicely ;)

[jsmurphy]

bigmf- thanks for the input. It's a US gal. recipe, but that's a good point you made.

[sallad]

170F is too high of a mash temp.

it just dawned on me that, yes 170 is too high for a mash temp, but its a good starting point for your water temp. In other words, if you heat your water to 170, then add your grains, you expect to lose about 10-15 degrees, which should put you in the upper 150s. so, maybe your instructions were just a little unclear on that point, jsmurphy...

[jsmurphy]

That's exactly what I did.

[sallad]

well, great then.. sounds like everything is up to par and you just got a diluted sample, as you said. and you'll be enjoying some wonderful homebrew in a few weeks!

[Fast_Eddy]

To avoid that confusion - you could say that the strike water was 170F. Just an FYI.

[jsmurphy]

Fast_Eddy, yep that's what the recipe says, "strike at 170*"

Sorry for the confusion...

[Fast_Eddy]

Originally posted by jsmurphy
Fast_Eddy, yep that's what the recipe says, "strike at 170*"

Sorry for the confusion...

NP....everybody is here to learn. ;)