Refractometer

[Swiller]

Hi Guys

This has probably been posted before.
I would like to buy a refractometer can
anyone advise me which to get please?
I have looked on Fleabay and there are
quite a few some measure in Brix and
need a conversion and I didn't see any
that had straight ABV measurement.

cheers!

[richc]

You can get refractometers with gravity scales on them but Brix is pretty normal and isn't really a problem. You can use a scale to convert but multiplying by 4 and adding 1000 gets you to a reasonably accurate number for lower gravity beers.

It's worth noting that once fermentation has started you will need to do a calculation whatever the scale is as alcohol content changes the reading.

[Dennis King]

You can use a site like this one for easy conversation.

http://brew.stderr.net/refractometer.html

[jmc]

Its not as complicated as it sounds and they are a boon, especially if you do AG and are mashing / sparging.

Very little waste, a few drops from FV tap and you've got enough to measure SG

You can use online calculators, but mostly I use an Excel sheet I've printed off that shows FG (eg 1012) based on starting and final refractometer reading in brix

[Dennis King]

You can use online calculators, but mostly I use an Excel sheet I've printed off that shows FG (eg 1012) based on starting and final refractometer reading in brix

I've also printed a sheet which is on the wall, but you will need a calculator to take a reading while fermenting.

[Kev888]

You can get them with SG scales too - like this one from discount_instrument hong kong.

I 'think' thats the one I got (my link expired so i can't be sure) and it seems to check out against my failthful old hydrometer, though as with all refractometers you need to compensate for alcohol post-fermentation. I think ideally I'd prefer a narrower range; 1.120 is unnecessary for any beer that I'd brew and its a bit tricky to be very precise with such fine/compressed graduations, but its probably no worse than trying to judge a standard hydrometer and 'a lot' more convenient for dealing with hot wort so I'm pretty happy with it for my purposes.

Cheers
Kev

[Swiller]

Thanks guys much appreciated.

J

[timb]

Hi, bought this on e-bay this week. Ordered Monday and arrived Wednesday. Seems to be exactly the same as my local brewery uses.Using it today and works fine.

[Swiller]

Just ordered one thanks timb.

[Swiller]

Refractometer arrived today so I thought I would try it out
on a beer I have which is part way through fermentation.
I get a reading of 13 which using an online converter gives
1.053 (it's a strong Belgian ale). I thought I would just check the same beer with my hydrometer which gave a reading of 1.030.
I tested the refractor with water at 20c and had a zero reading so I assume it's calibrated correctly and the beer I tested with the hydrometer was also at 20c I wonder why the discrepancy?
Tasting the beer it's not sweet so I would believe the hydrometer.

J

[GrowlingDogBeer]

The thing to be aware of is that they measure the sugar content of the liquid, but the way it measures gets affected by alcohol, so as soon as fermentation is underway the reading it gives you is false, and you have to calculate the FG using a calculator.

You need to know the original BRIX reading, in order to be able to calculate the current Gravity as you need to take into account the amount of alcohol in the solution as well.

You can use this calculator.

http://onebeer.net/refractometer.shtml

[Swiller]

Thanks Steve, I only know the OG was 1.080 can I put this in
the calculator as a Brix reading which would be 19.31?

J

[GrowlingDogBeer]

Yes, if you put an Original BRIX of 19.31 in, then a final BRIX of 13 it gives you a final Gravity of 1.034. Closer, but still 4 points out for some reason.

[Swiller]

Thanks again Steve I re-calculated
using the link you posted and it
checks out equal to the hydrometer
reading I was getting.
I knew I was doing something wrong!

Cheers,

J