Hydrometer reading(FG)=1.010 Brix=7.1%???

ANewrBrewr · 06-17-2011, 01:14 AM

I've got a batch of IPA that has been in the primary for 2 weeks and the current hydrometer reading is 1.010 yet using a refractometer the brix % is 7.1. I've looked up a few different equivalency charts for brix->specific gravity and my readings do not match up??? I've also heard that brix readings are not accurate after fermentation has ended. Is this what is going on? I would much rather use my refractometer to do readings as it is much easier for me to read and use, but if a hydrometer is the way to go then I guess I'll conform.
Just wanting to here some feedback from the experienced brewers.
Cheers.

**ajdelange** · 06-17-2011, 02:15 AM

Stick with the hydrometer. In brewing refractometers are great for monitoring the decline in extract as sparging proceeds but they really aren't good for much else.

JimGossett · 04-01-2012, 05:45 PM

Quote:

Originally Posted by ANewrBrewr

I've got a batch of IPA that has been in the primary for 2 weeks and the current hydrometer reading is 1.010 yet using a refractometer the brix % is 7.1. I've looked up a few different equivalency charts for brix->specific gravity and my readings do not match up??? I've also heard that brix readings are not accurate after fermentation has ended. Is this what is going on? I would much rather use my refractometer to do readings as it is much easier for me to read and use, but if a hydrometer is the way to go then I guess I'll conform.
Just wanting to here some feedback from the experienced brewers.
Cheers.

Alcohol contributes to a Brix reading, yet is not sugar. Alcohol negatively affects SG, because alcohol is less dense than water. So, after fermentation begins, a Brix reading will over-estimate remaining extract and a hydrometer reading will underestimate remaining extract.

Ma23456 · 04-01-2012, 05:50 PM

The ethanol will affect your brix reading because of its polarity so it messes with the light hydrometer all the way

JimGossett · 04-01-2012, 09:24 PM

Quote:

Originally Posted by Ma23456

The ethanol will affect your brix reading because of its polarity so it messes with the light hydrometer all the way

Not sure what you mean by "messes with the light." There are methods for measuring ethanol in water that rely on refractometry. In fact below about 20% ABW, there is a quite linear response between ethanol and apparent Brix in water. The nature of refractometry is that it is based on things "messing with light."

**ajf** · 04-01-2012, 10:12 PM

Quote:

Originally Posted by ajdelange

Stick with the hydrometer. In brewing refractometers are great for monitoring the decline in extract as sparging proceeds but they really aren't good for much else.

Actually, they are also very good for determining when fermentation is complete for those people who feel the need to take gravity samples on a daily basis. When the Brix stops dropping, fermentation is complete. Then, you can take a single gravity reading to find out what the FG really is, leaving you with a lot more beer to drink than if you had taken multiple hydrometer samples.

-a.

DSmith · 04-02-2012, 12:47 AM

If the IPA original gravity was 1.057 then 7.1% Brix and 1.010 final gravity make sense with the ProMash refractometer calculator.

**iaefebs** · 04-02-2012, 01:42 AM

Post is 10 mo old. I doubt OP needs an answer now. DSmith had the right answer though.