Brix vs. SG

Haven't been able to find an answer to this in all my reading and searching through forums. Is there any advantage to using the Brix scale as opposed to the SG scale for measuring wort? I just bought a refractometer and was gonna start using the brix scale but couldn't really see any reason to learn a new measurement system.

You only need 2 or 3 drops of wort to get a brix reading, which is the raw data your refractometer will give you which needs to be converted to SG. You need quite a bit more to get a good hydrometer reading for a direct gravity reading, and you have to cool it, which can take a very long time with boiling wort.

Ah, right there might be a good reason to learn the Brix scale: many dual scale refractometers have bogus SG scales, like mine (bought in December from a retailer that does business here, fwiw). The higher the Brix reading, the greater the error in the SG reading....

Cheers!

Beardedterror said:

You only need 2 or 3 drops of wort to get a brix reading, which is the raw data your refractometer will give you which needs to be converted to SG. You need quite a bit more to get a good hydrometer reading for a direct gravity reading, and you have to cool it, which can take a very long time with boiling wort.

Click to expand...

i've been using a hydrometer for 4 years now and the idea of using 2 or 3 drops is why I wanted the refractometer. I just learned that after the beer is fermented refractomers aren't accurate. I'll have to type it in beersmith to convert it and give me an accurate reading. not a big deal. i'm just trying to get educated on my new toy

day_trippr said:

Ah, right there might be a good reason to learn the Brix scale: many dual scale refractometers have bogus SG scales, like mine (bought in December from a retailer that does business here, fwiw). The higher the Brix reading, the greater the error in the SG reading....

Cheers!

Click to expand...

yeah i was reading about that. I'll probly just have beersmith convert all the brix readings to sg and stick with that. I just like the idea of only using a few drops instead of 4oz or so to take a measurement

As you realize the sample reading with a refractometer is a couple drops compared to 4 or 6oz. It sounds to me that you are using BeerSmith 2 so there is really no learning curve, you navigate to the tools folder and plug in numbers and it will convert your Brix reading to SG. I remove the air lock and stick a straw through the opening and gather a sample. I could check every day for a month or 3 and not use as much as a single hydrometer sample would take.

As day trippr pointed out stay away from the SG scaled refractometers and just use Brix.

If you don't have Beersmith or a application in whatever program you use there are several online calculators that are free to use.

Multiply your brix by 4 and you get your SG or close to it.

14 brix = (14 x 4 = 56) so your SG is 1.056

Its that simple, and if you are only after your efficiency then you can really stop there.

Since Brix/Plato are generally read with a decimal point (ex 12.3) you are able to get a slightly higher degree of precision. This is one reason why Plato is the standard scale used by most commercial brewers.

Calichusetts said:

Multiply your brix by 4 and you get your SG or close to it.

14 brix = (14 x 4 = 56) so your SG is 1.056

Its that simple, and if you are only after your efficiency then you can really stop there.

Click to expand...

This only works for converting pre boil / post boil to SG. Once the wort starts to ferment that multiplying Brix by 4 is no longer valid. For example a wort of 14 would be 1.055 which is close enough to times 4. However, once converted to alchohol a reading of 7 will convert to 1.011 SG (not 1.028 using your method)

iaefebs said:

This only works for converting pre boil / post boil to SG. Once the wort starts to ferment that multiplying Brix by 4 is no longer valid. For example a wort of 14 would be 1.055 which is close enough to times 4. However, once converted to alchohol a reading of 7 will convert to 1.011 SG (not 1.028 using your method)

Click to expand...

If you are referring to reading with a refractometer, then you are correct due to the difference in the refractive index of ethanol... however, if you're reading a floating hydrometer the Plato and SG readings will continue to be relative

iaefebs said:

This only works for converting pre boil / post boil to SG. Once the wort starts to ferment that multiplying Brix by 4 is no longer valid. For example a wort of 14 would be 1.055 which is close enough to times 4. However, once converted to alchohol a reading of 7 will convert to 1.011 SG (not 1.028 using your method)

Click to expand...

OF course, this is why I mentioned that if you are only after efficiency you are all set...

Calichusetts said:

OF course, this is why I mentioned that if you are only after efficiency you are all set...

Click to expand...

I was just trying to clarify. I see so many posts where people mention that they don't use a refractometer after fermentation starts because the readings are inaccurate. I believe it is because they are not using a conversion calculator and are either using a chart to convert Brix to SG or are using a refractometer that displays SG only, or one that displays both scales linear. Since you had supplied an example of pre ferment numbers I just took your example and wanted to show it to the next step. (during ferment)

I printed the relevant pages from this PDF file and keep it w/my instruction sheet. Can make quick conversions w/o looking at the computer. But I just noticed it was created, the charts, in 1942. Think that there have been any changes????
http://www.boulder.nist.gov/div838/SelectedPubs/Circular%20440%20Table%20114.pdf