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Estimating ABV

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Phoenix1854

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Hey all, I have a Cranberry honey Belgian Dubbel fermenting right now, but unfortunately I did not have a means to measure the OG because I had an accident with my refractometer and ordered a replacement. After a week of fermentation, the gravity reading was at 1.046 and fermentation is still going pretty strong. I plan to take another reading this weekend once it has slowed down. Anyone have any ideas what the OG might have been? On a side note, initial results after one week are very promising!
 

jrgtr42

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With an exact recipe, and exact volumes, it should be possible to get in the close ballpark of your OG.
You can plug it into one of the brewing calculators, (I use Brewers Friend) and it should give you an idea.
 
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Phoenix1854

Phoenix1854

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Thanks! I found one but it didn't output any logical results based on my reading a week after fermentation began. I think the original recipe was supposed to be 7.5%, but I added 4 ounces of honey and the cranberries, which I am sure will increase the final ABV (it's a 1 gallon batch).
 

VikeMan

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How much cranberries did you add and in what form?
 

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Thanks! I found one but it didn't output any logical results based on my reading a week after fermentation began. I think the original recipe was supposed to be 7.5%, but I added 4 ounces of honey and the cranberries, which I am sure will increase the final ABV (it's a 1 gallon batch).
If you put the original recipe in the software, along with the honey (and the cranberries will likely be negligble, there isn't much sugar in them), you can get the estimated OG. The one now, especially with a refractometer, is useless. (Refractometers measure the refraction of light in a sugar solution, so once alcohol is in the mix and the light is skewed as a result, the reading is meaningless without an OG).
 
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Phoenix1854

Phoenix1854

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If you put the original recipe in the software, along with the honey (and the cranberries will likely be negligble, there isn't much sugar in them), you can get the estimated OG. The one now, especially with a refractometer, is useless. (Refractometers measure the refraction of light in a sugar solution, so once alcohol is in the mix and the light is skewed as a result, the reading is meaningless without an OG).
Yeah I figured the cranberries might be negligible, but thought the honey might add a significant enough boost. I guess I can just track fermentation by taking the readings from here on out and see where the FG falls.
 

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You cannot use a refractometer on its own to measure gravity once fermentation has happened. The alcohol in solution changes the refractive index of the liquid. You'll have to use a correction factor if you are only using a refractometer. Check out the Brewer's Friend page/calculator.
 

BrewnWKopperKat

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but unfortunately I did not have a means to measure the OG
With refractometer and hydrometer measurements of FG, one can estimate/calculate OG.

There are a couple of "online" calculators (Northern Brewer has one). If you can't find one, let me know & I check my notes for a link.
 

VikeMan

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I added 8 ounces of whole cranberries once the wort cooled to about 170 degrees.
I meant to also ask about the batch size, but/so here are a few estimates, given "X" gallons of a 7.5% ABV beer, with 4 ounces of honey and 8 ounces of cranberries added, accounting for the sugars and water in the cranberries (and the honey)...

1 Gallon Batch: 8.4%
2 Gallon Batch: 8.0%
3 Gallon Batch: 7.8%
5 Gallon Batch: 7.7%
 
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Phoenix1854

Phoenix1854

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Thanks everyone! This has been really helpful. I did find some online calculators so i will try those out once I get to that point. Still has to ferment/age for another three weeks or so. But it seems to be coming along nicely!
 
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Phoenix1854

Phoenix1854

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I meant to also ask about the batch size, but/so here are a few estimates, given "X" gallons of a 7.5% ABV beer, with 4 ounces of honey and 8 ounces of cranberries added, accounting for the sugars and water in the cranberries (and the honey)...

1 Gallon Batch: 8.4%
2 Gallon Batch: 8.0%
3 Gallon Batch: 7.8%
5 Gallon Batch: 7.7%
This is helpful, thanks! I was wondering how much the honey would effect final ABV.
 

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Thre arealso calculators you can put on your smart phone , I use the "Brewzor Calculator". It is pretty intuitive and has all kinds of calculation and coversion factors.
 

VikeMan

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This is helpful, thanks! I was wondering how much the honey would effect final ABV.
In your case, the honey would increase the ABV, but the cranberries would reduce it.
 
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