Newbie Post- Brix vs SG

[RandyB]

I have been reading in the wings for several weeks now and have my first questions. Due to overhead space limitations, I would like to sample my wines using the Brix method as opposed to using a Thief. Using a small pippet to take samples and then use my Refractometer will allow me to miss my overhead cabinets, thus allowing maximum area for my Carboys. I tried my first batch primary fermentation this way and used various conversion tables to convert Brix to SP. Each conversion table gave me a different SP, so I'm not confident that this is the way to go.


Long-story-short, is the Refractometer (Brix) method accurate enough to use for the primary and secondary fermentations?


I have an Aspirator for racking and degassing, so I shouldn't have space problems with the other steps, just the testing of the Alcohol content.


Sorry I don't have a more intriguing question for my first, but this won't be my last posting.


Thanks in advance,

 

[grapeman]

As the sugars are converted to alcohol, brix readings begin to skew- or are less accurate. There are conversion tables- but they are primarily for beer that take this into account. It would be best if you could figure a way to take SG readings instead.

 

[Wade E]

Welcome RandyB! I dont know if a refractometer is the way to go once the fermentation has begun as I dont use 1, I use a hydrometer which is a very cheap tool and is very accurate for wine making.
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Triple Hydrometer Specific grav, Potential ETOH, Sugar


SG scale 0.78-1.150; potential ABV scale 0-16%; sugar per liter scale 0-34.
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<td width="2%"><div align="right">$5.99</td></tr></t></table>I actually use the Thermohydromter as you cn tell the temp at the same time but it is a few more bucks.
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Thermohydrometer


Temperature 0-120° F; SG scale 0.850-1.160; potential ABV scale 0-20%; balling scale 0-35.
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<td width="2%"><div align="right">$14.99</td>
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[smurfe]

You can use it during fermentation. Just do a little math and your good to go.


Here is the formula

Formula for compensation of ethanol effect on refractometer: SG=1.001843-0.002318474(OB)-0.000007775(OB^2)-0.000000034(OB^3)+0.00574(AB) +0.00003344(AB^2)+0.000000086(AB^3)
SG = Specific Gravity, OB = Original Brix, AB = Actual Brix (Brix Readings During Fermentation)


Seriously though, it can be done but variables are out there. For example, I found out the hydrometer I have is not very accurate. I have compared it against 3 hydrometers that all get the same reading on a sample and got various Brix readings. Mine is supposed to be ATC but evidently they forgot to install that option as the readings will vary widely even at lower temps.


I tried it a while back on a batch of beer during the boil to see when I hit target gravity. I started at an 8 Brix at the end of the mash. I boiled for an hour and at end of the boil I had a Brix of 8.2 which is pretty well impossible. I checked a sample with the hydrometer and the Brix should of been around 12. I tried it again on my net brew and it was 3 points off. I then threw it in the trash can. Back to the hydrometer again although I did order a better quality refractometer and will see how it works.

 

[RandyB]

I had read that once fermentation begins, the Brix – SP relationship is skewed. The formula that I was toying with indicated that it compensated for the fermentation. But again, my Brix conversions to SP were not consistent with my Hydrometer readings. I might add that the conversions were MS Excel worksheets I located on the web. As Smurfe illustrated, I wasn’t about to manually convert the two!
Oh well, I’ll have to find a way to sample so I can continue utilizing the Hydrometer.
Thanks for the feedback,

 

[Wade E]

Wine thief!
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Wine Thief/Test Jar Combo Fermtech


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<td width="2%"><div align="right">$8.49</td></tr></t></table>This is what i use and even if the wine is too shallow all you have to do is jig it up and down in the shallow carboy and it will keep filling up.