02-03-2013, 08:13 PM
Liked 508 Times on 470 Posts
Originally Posted by saxman1036
I had a similar problem yesterday with a 5.5 gal Imperial Stout all-grain batch of mine. Here was the recipe...
18 lbs Pale Ale
.6 lbs Roasted Barley
.6 lbs Choc Malt
.6 lbs Med Crystal
.6 lbs Black Malt
I mashed the whole deal in a 10gal cooler.
This is only my second all-grain brew, so I expected that with that many grains in a 5.5 gal batch I was planning on only about 60% efficiency. If I hit that, I expected to land in the mid-80's with my gravity readings. I was a little lower than that even, and I came in at 56%, and after stirring the wort, I measured 1.062 for 6.8 gallons of wort... so 1.077 equivalent for the 5.5 gallons I wanted.
I was bummed, but I sucked it up and figured "I'm just gonna boost this sucker up a little." After some research on the forums here, I added 1.5 lbs of extra light DME and 1/2C of molasses (~6.2oz), both within the last 15 minutes of the boil. These *should* have added ~16 points to my gravity. After chilling & moving to a carboy, I hit *exactly* the volume I wanted (fist-pump!), meaning I didn't need to top off with any water. Needless to say I was shocked when my gravity reading was only 1.083, as opposed to the 1.093 I was expecting. I was pissed, so I shook the &*%$ out of that carboy for a couple minutes. There was foam all the way to the top of the bung hole. And the new reading... you guessed it... 1.083.
Where the %$#@ is all my sugar going?? The ONLY thing I can think of is that the gravity of the wort is so crazy dense & heavy that I can't possible mix shake the carboy enough to get an accurate & representative sample of its gravity.
Alright, now that I've calmed down, a couple more notes on my issues...
1. I've had this problem with other beers recently. I generally brew big beers (at least 1.075), and the higher target gravity ones are further off from the target than the lower ones.
2. I did branch-out recently and brewed a lager. The expected OG was 1.047, and I came in at 1.048. I was super happy/confused.
3. I have purchased and tested a new hydrometer, it works fine.
4. I am considering buying a mix stir.
Is it possible that even after vigorously splashing and shaking the carboy that many of the sugars are still sitting on the bottom of the carboy and that I can't reach them with my siphon?
This is an AG batch and the issue would not be the same as an all extract batch as the OP had.
There are many variables involved with the mash and water volumes that can effect you OG so the two types of brewing issues cannot be compared.
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