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Old 03-25-2011, 06:24 AM   #1
bmantzey
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Jun 2010
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I just finished a Celebrator Doppelbock clone and checked the gravity.

After very carefully reading the hydrometer, I get 1.063 @ 75.
The target OG is 1.080 - 1.085.

How the heck can I be 20 points below target?



 
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Old 03-25-2011, 07:01 AM   #2
djsethall
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Extract? All grain? Lots of variables. Maybe post the recipe, your method and other such important variables



 
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Old 03-25-2011, 07:09 AM   #3
bmantzey
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Jun 2010
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Good point.

Sorry, I'm all grain. Here's the recipe:

Dark Munich Malt (global): 28oz
65L German dark crystal: 8oz
chocolate malt: 5oz
german pilsner malt: 12lb
Dextrin malt (carapils): 14oz

Infusion mash.

The grain bill was a little high for my setup, so I split it all in half. I was very careful measuring everything and I'm sure I would have realized it by now if I omitted something.

I'm not too confident about my thermometer. I actually use 3 or 4 different ones and go with which reading is most common. I'm wondering if my mash temp was too low during one of those two mashes, but 20 points? I don't know.

 
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Old 03-25-2011, 01:36 PM   #4
kanzimonson
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ALWAYS take a preboil gravity reading. This is recommended over and over on the forums in every single "First AG batch" thread and yet people always skip this. Had you done it, you could have added DME and hit your target.

Big grain bills are frequently trouble for efficiency, and the fact that you split it in half only increases the problem. Basically, you just weren't able to sparge enough.

Just settle for the fact that you made a bock instead of doppel... it will probably be delicious and rich. I don't like turning our beers into experiments after they're brewed, especially when the problem is gravity. If it comes to fixing diacetyl or acetaldehyde, that's another story.

 
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Old 03-25-2011, 02:12 PM   #5
Homercidal
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On a big beer there is a much greater gravity change in a small efficiency miscalculation. I would not worry about your thermometer if you are using several and using the common readings. That should be pretty close.

There are several things that can affect your efficiency, such as planning wrong, poor crush, sparge method, etc.

As the above poster mentioned, it best to take preboil readings when you are starting out, so you can adjust with extract, or top off with more water if need be. Once you have several batches under your belt and can be confident in your equipment and process, you can probably safely enter an efficiency into your software and come very close.

 
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Old 03-25-2011, 02:19 PM   #6
kanzimonson
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My system is pretty dialed in, but I still make efficiency adjustments based on the grain bill size. For me, if the bill is less than 14#, I can usually get at least 78-80%. For 14-17# I plan for 75-78%. For 17-20# I use 70%. Anything greater I'll usually plan for 65%, but when it's bigger than 20# I'm usually doing some sort of partigyle.

I always aim low so I can be pleasantly surprised when my preboil gravity is a few points higher than expected.

 
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Old 03-25-2011, 02:33 PM   #7
electric_beer
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I'd say the crush. It's something easy that can royally screw your eff. If you buy from a LHBS or online, its possible that their mill got a number of problems that would effect your crush. If someone bumped into it and changed the setting even a little bit it can mess it up (happened to me, but my LHBS gave me store credit cuz they noticed it after I left). Not to mention if someone milled items that they perhaps shouldn't (ie flaked items) it can be functioning but perhaps not well...when you rely on other people's crush you never know what you'll get. Bottom line. Which is why you should always QC the grains before leaving the store.

 
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Old 03-25-2011, 03:18 PM   #8
homebrewedipa
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Quote:
Originally Posted by kanzimonson View Post
ALWAYS take a preboil gravity reading. This is recommended over and over on the forums in every single "First AG batch" thread and yet people always skip this.
How do you guys take preboil gravity readings? Do you siphon off enough sweet wort to fill a hydrometer jar, wait for it to cool to 60F and then take the reading? Or do you just take it and try to adjust for temperature?

 
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Old 03-25-2011, 03:27 PM   #9
kanzimonson
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Before I had a refractometer, I used to put a small kitchen pot in the freezer at the beginning of brew day. After I filled my kettle, I vigorously stirred it for a minute, then I'd draw off about 3-4oz, put it in the frozen pot, swirl for a minute or two, and it was usually around 70-80* at this point.

 
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Old 03-25-2011, 05:37 PM   #10
erikpete18
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Quote:
Before I had a refractometer
A refractometer makes this so much easier. If you can find one of the ebay ones, they're only $30-40 and this way you can check at any spot you want to see how you're coming along (first runnings, sparges, pre-boil, post-boil, etc.). They don't work well for post-fermentation, but if you've got the money they can make understanding what things help efficiency in your system and what things don't help much a lot easier.



 
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