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Old 04-02-2012, 11:46 AM   #1
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Default Inconsistent OG

I brewed by first braggot yesterday. When I tried to measure OG I was getting inconsistent readings. The sample seemed stratified and there was floating particles in it (either from the hops or the yeast energizer).

The first sample read off the scale high on my refractometer (> 1.135). The second sample I let settle for five minutes and took a few drops off the very top. That measured 1.127. The recipe was supposed to come out at 1.135 according to Beersmith.

Any thoughts?

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Old 04-02-2012, 12:01 PM   #2
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I'm not nearly as familiar with refractometers as your run of the mill hydrometer, but hops or other undissolved particulates shouldn't affect the OG...only dissolved stuff counts, at least as it applies to hydrometer readings. Perhaps this is something unique to refractometers?

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Old 04-02-2012, 12:16 PM   #3
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I didn't think so either, but I've never done a mead before so I didn't know if the stratification thing was common?

The first reading was WAY off the scale high (like 1.150 or 1.200 !) so I was worried about fermentation. This morning everything is bubbling nicely, but it would be nice to know the 'real' OG so I can estimate ABV when it's done.

EDIT: Forgot to mention that I measured OG after pitching yeast. Not sure if that matters.

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Old 04-02-2012, 01:19 PM   #4
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Further to stratification; you can definitely get stratification in the entire batch after adding honey; if it doesn't get fully dissolved you can get honey settling and concentrating at the bottom of the carboy. That being said, I've never heard of honey stratifying in a sample after it is pulled off the top for gravity testing.

I'd suspect that your OG probably lies somewhere in the area of your estimated gravity and your second reading.

Does anyone else who uses a refractometer know if there is any other reason why this could have happened?

EDIT: regarding your OG, I was thinking further...the main variables are your efficiency on the grain portion, and the PPPG of the honey (assuming your fermentation volume is fairly accurate). If your efficiency was what you expected (did you check a pre-boil gravity or post boil gravity before adding the honey?), or if this was an extract batch, then look to the honey. Depending on the brewing software settings, you could get very different expected gravities; for example, I use ProMash, which for some reason defaults Honey to 1.042 pppg, which is probably a bit high...average honey tends to be ~ 1.036-1.038...I generally manually set the pppg down to 1.037, and this tends to jibe more with what I get in real life. The point being is that your second measured gravity may be dead on as expected, if you knew the actual PPPG for your specific honey compared with what your calculator was assuming...

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Old 04-02-2012, 01:21 PM   #5
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It may be possible that your honey is settling out is it wasn't combined completely with the water. I had that problem with my first batch of JAOM.

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Old 04-02-2012, 03:59 PM   #6
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Quote:
Originally Posted by biochemedic View Post
EDIT: regarding your OG, I was thinking further...the main variables are your efficiency on the grain portion, and the PPPG of the honey (assuming your fermentation volume is fairly accurate). If your efficiency was what you expected (did you check a pre-boil gravity or post boil gravity before adding the honey?), or if this was an extract batch, then look to the honey. Depending on the brewing software settings, you could get very different expected gravities; for example, I use ProMash, which for some reason defaults Honey to 1.042 pppg, which is probably a bit high...average honey tends to be ~ 1.036-1.038...I generally manually set the pppg down to 1.037, and this tends to jibe more with what I get in real life. The point being is that your second measured gravity may be dead on as expected, if you knew the actual PPPG for your specific honey compared with what your calculator was assuming...
It was an extract recipe (Hefty Braggot from Compleat Meadmaker).

Fermentables:

6lbs Amber DME
12lbs Honey (Star Thistle raw honey from Sleeping Bear Farms)

I can't find the PPPG of honey in Beersmith. It says potential of 12lbs of honey is 1.034 (Yield: 75%)? Not sure how to convert that to PPPG.

After adding the honey I poured the must in a 5 gallon carboy and topped off with water to nearly the top of the container (as far as I could without the foam overflowing). So it was very close to a full 5 gallons.
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Old 04-03-2012, 02:05 AM   #7
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Quote:
Originally Posted by bk0 View Post
It was an extract recipe
6lbs Amber DME
12lbs Honey (Star Thistle raw honey from Sleeping Bear Farms)

I can't find the PPPG of honey in Beersmith. It says potential of 12lbs of honey is 1.034 (Yield: 75%)? Not sure how to convert that to PPPG.

After adding the honey I poured the must in a 5 gallon carboy and topped off with water to nearly the top of the container (as far as I could without the foam overflowing). So it was very close to a full 5 gallons.
If you didn't mix well after topping off, this could cause funky readings...

I think what your software means is that the PPPG is set at 1.034. If I recreate this recipe in ProMash with the honey set at 1.034, it predicts 1.137 which is pretty much what you had gotten for expected OG.

Since you didn't do a mash, the concept of efficiency really doesn't come into play. You get whatever fermentable:unfermentable ratio you get with the DME, but the contribution to gravity is pretty much a constant for a given type of DME. Honey, as we've been discussing is more variable, but is, for all intents and purposes, 100% fermentable, so the attenuation of honey is always 100% within the alcohol tolerance of your yeast.

At some point, when times allows, you could be well served to actually incrementally measure the volume levels in your carboy; ie, add water a measured 1/2 gal at a time and label the volumes...some carboys hit their target volume lower than the top of the neck, which could, possibly explain a slightly lower than expected gravity.

The bottom line is you'll never know your exact gravity, but RDWHAHB, and just round it off to the nearest percent!
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Packaged: Dark Munich Citra SMaSH, Mayan Stout, Caramel Quad, Basic Spiced Cider, Spur of the Moment Graff
Recent Meads: Mead Day '11 Ginger Metheglin, Mead Day '12 Traditional (orange blossom) Mead, Fresh Simple Cyser '12, Cherry Melomel, Belgeglin, Bochet
Primary: Nada!
Secondary: Why do I keep this line here...?
Bulk Aging: Cocobochet
Planned: Hop Metheglin #3 (NZ hops), Trad. Gesho T'ej
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Old 04-03-2012, 10:24 AM   #8
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OK, that's good enough for me.

Thanks for your help!

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Old 04-09-2012, 02:42 PM   #9
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One week after pitching, I consolidated the braggot into a single carboy. Took a gravity reading, it's at 1.043 (12% ABV).

Tasted like...hoppy, sweet vomit. Not good. But it's not even done primary fermentation yet so I'm not going to worry.

Is it worth putting in another 1/4 tsp of yeast nutrient?

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