Refractometer help

[robby6pack]

Could someone walk through the steps of reading FG on a refractometer? I get that only the OG will be the same as the BRIX number for wort before fermentation. For FG do I read the gravity and convert to BRIX or just read the BRIX side of the refractometer? Then use a conversion table to find the ABV? Please keep it simple with only OG and FG. Thanks

 

[day_trippr]

I use the Brix reading and convert because the SG reading from my particular refract is guaranteed to be off as gravity increases.
But, there are refracts with better correlation between Brix and SG scales for beer applications than mine...

Cheers!

 

[Robert65]

Use the calculator at Brewers Friend, there's a link under "brewing software" in the menu right here on HBT. It will tell you what to do.

 

[bleme]

Also know that even with calculator correction, you are still only going to get a ball-park number. It can tell you if there hasn't been a gravity drop in three days. It can tell you that your beer is roughly 6.5% ABV. I would NOT rely on it to tell you when to spund, unless you are able to perfectly recreate a previous beer and are going by it's readings.

 

[jrgtr42]

Honestly, the Brewers Friend calculator is pretty much on. When I got my refractometer, for the first several batches I would back up my readings with my hydrometer. This one time I got something way off, I went back through and realized it was an ID-10-T error - bad reading on my end.
I haven't bothered with my hydrometer for the past bunch of batches.

 

[Robert65]

Also know that even with calculator correction, you are still only going to get a ball-park number. It can tell you if there hasn't been a gravity drop in three days. It can tell you that your beer is roughly 6.5% ABV. I would NOT rely on it to tell you when to spund, unless you are able to perfectly recreate a previous beer and are going by it's readings.

The Brewer's Friend calculator appears to use the Novotný quadratic formula, which I also use. I have tested it over and over, and it is dead accurate, confirmed with precision hydrometer readings. In fact, you get a more accurate measurement than with a hydrometer, because suspended particles and CO2 skew those significantly unless your sample is filtered and degassed. I do indeed use refractometer to spund. Also use it on my FFT, during the mash, everything. Lots of expensive precision lab hydrometers gathering dust. That said, I do use a digital refractometer made for brewing. That's very easy, no guessing where the fuzzy line is supposed to be or worrying about a "correction factor" for maltose.

 

[cmac62]

Honestly, the Brewers Friend calculator is pretty much on. When I got my refractometer, for the first several batches I would back up my readings with my hydrometer. This one time I got something way off, I went back through and realized it was an ID-10-T error - bad reading on my end.
I haven't bothered with my hydrometer for the past bunch of batches.

jrgtr42 you are giving away your military past with ID-10-T Error. I remember sending rookies all over the Carrier looking for the ID-10-T forms. LOL.

 

[hyder124]

so, are y'all saying that its best to use the BRIX side of your Refractometer? I have always used the SG 1.XXX side going into fermentation and taken a final at keg or bottling and did the input on the calculator on Beer Smith, but as a rookie knowledge is welcomed.

 

[Robert65]

I've seen some of those handheld refractometers with SG markings across from the Brix, and the SG markings are often incorrect -- they don't line up right. Just use the Brix markings, and let the calculator convert to SG.

 

[jrgtr42]

jrgtr42 you are giving away your military past with ID-10-T Error. I remember sending rookies all over the Carrier looking for the ID-10-T forms. LOL.

TBH, I am not a military person (though I've known enough folks who have been.)
I was an IT major in college, and that's where I picked it up. I've used it on and off ever since then.
I would set up error messages in my programming examples returning a response: "ID-10-T error. You can't DO that, bonehead!"

 

[donovanlambright]

I'm glad you posted this. I've been puzzling over the various online calculators. Do I understand correctly that the Brix reading on the refractometer is correct after fermentation (unlike specific gravity) and does not require any conversion?

 

[Robert65]

No. As soon as fermentation begins and there is alcohol present, refractometer readings need correction. Alcohol refracts light differently than a sugar solution, which is what refractometers are calibrated to read, hence the need for correction.

 

[donovanlambright]

Thanks! I was confused that my refractometer shows specific gravity but all the calculators require Brix. It sounds like sg is not always accurate on these instruments?

 

[day_trippr]

Correct - and some are worse than others...

Cheers!

 

[Gresco]

I've seen some of those handheld refractometers with SG markings across from the Brix, and the SG markings are often incorrect -- they don't line up right. Just use the Brix markings, and let the calculator convert to SG.

Curious about this difference, from reading a lot of reviews from the cheap refractometers on Amazon, it seems that most of the SG scales are off... is it even worth getting a dual scale? Or do most people just convert the Brix?

 

[day_trippr]

I have one of those refracts that the SG scale becomes increasingly inaccurate as Brix increases. So I just use the Brix side and use BeerSmith to translate...

Cheers!