Refractometer

[scooterism]

I'm thinking of buying a refractometer, is this a good idea or a bad idea?

If it's a good idea, which one is a reccomended buy?

 

[nosco]

Id love to be able to use mine but its been unreliable so far. JZ on brew strong said he used to caibrate different refractometer to different gravities to get an accurate reading. I think they are only used to get a ball park reading but a hydro is more accurate. A lot of people use them so there must be something in it.

 

[evoo4u]

I use mine to check final runnings. Used it earlier this afternoon and it read 4%, so approx. 1.016, on the last of the sparge, so happy with that. Recommended not to let the final runnings sink below 1.010.

Then post-boil reading of 12%, so approx 1.048 which is what Beersmith predicted with my efficiency dialled in.

The benefit is that only three drops are needed to get a reading, rather than 100mL or so for a hydrometer. The down-side is that they're really only good for wort with no fermentation having taken place, unless you want to get into fancy calculations taking OG, temperature, a few other things and mother-in-laws favourite scone recipe into account! (OK - I made up the last one...)

So not as necessary a bit of kit as a thermometer, hydrometer, and spray-pack of Starsan, but useful for some parts of the brewing process.

And mine? A fleabay job for about $20 from memory. Works well.

 

[Bribie G]

With the particular software I use (BrewMate) my refrac is ideal for seeing whether I have hit the expected efficiency as predicted.
I bought the full price one from a sponsor, that reads in Brix - which I ignore - and O.G. If looked after properly they would last forever, like a pair of binoculars or a sextant etc.
Wouldn't be without mine.

 

[TidalPete]

With the particular software I use (BrewMate) my refrac is ideal for seeing whether I have hit the expected efficiency as predicted.
I bought the full price one from a sponsor, that reads in Brix - which I ignore - and O.G. If looked after properly they would last forever, like a pair of binoculars or a sextant etc.
Wouldn't be without mine.

+1 but my eBay refrac is 10+ years old & only reads as Brix which means I have to use a conversion chart. No big deal.
Wouldn't be without it! The refrac I mean. LOL!

As Bribie says: If you take care of your gear, your gear will take care of you.

 

[Lowlyf]

I just bought one in ebay myself. $26 with free postage. Reads both Brix and SG. Can't go wrong ay?

 

[trevgale]

I think mine was about $40, it has brix and sg. I have found it to be highly accurate throughout all stages of brewing, just need to use an equation during fermentation. I used to compare it against a hydrometer but it was always spot on so I haven't pulled out the hydrometer in years.

I like to take daily readings during fermentation and put them into a spreadsheet to track the attenuation and fermentation rate. It is easy with the refractometer because you only need such a small amount. I think it would be too much of a pain for me to do with a hydrometer.

I wouldn't be without mine.

 

[scooterism]

I think mine was about $40, it has brix and sg. I have found it to be highly accurate throughout all stages of brewing, just need to use an equation during fermentation. I used to compare it against a hydrometer but it was always spot on so I haven't pulled out the hydrometer in years.

I like to take daily readings during fermentation and put them into a spreadsheet to track the attenuation and fermentation rate. It is easy with the refractometer because you only need such a small amount. I think it would be too much of a pain for me to do with a hydrometer.

I wouldn't be without mine.

Daily readings?, isn't that just asking for the funk to take over your brew?

Appreciate your reply tho.

 

[trevgale]

Not really, when I used a plastic fermenter I used to just grab a couple of ml for the refractometer, you wouldn't even see any activity in the airlock. Now I pressure ferment in 50L kegs, so it is all positive pressure so there is no way for the bugs to get in.

 

[Lyrebird_Cycles]

I like to take daily readings during fermentation and put them into a spreadsheet to track the attenuation and fermentation rate. It is easy with the refractometer because you only need such a small amount.

.

If you know your original extract (OE) in oP (or Brix), you can use this and the refractometer reading to derive the current alcohol.

(OE oP - current oP (by refrac)) x 0.96 = ABV.

Now that you have OE and alcohol you can work out apparent extract (the reading a hydrometer would give).

AE = OE - 1.77* ABV

Of course you can now combine these two to get

AE = 1.7 * Current oP(by refrac) - 0.7 * OE

These formulae are for beer and work reasonably well, best around "normal" alcohol / extract levels. I use different formulae for wine; one for whites and one for reds.

 

[Danscraftbeer]

I just have a KK cheap version and its a blessing to have in the equipment kit for quick easy measurements at any stage of mashing run offs and OG, anything pre ferment. Just a drop for a test at any temp. I say any temp because even a drop of boiling wort placed on the cold surface of a room temped refractometer you just let it sit on the bench for a few minutes if you want temp accuracy. Its very close tolerance compared to my hydrometer readings. Re mention I only use it for pre ferment readings.

 

[warra48]

I use one all the time to check my post mash SG and pre-ferment SG.
Mine reads both Brix and SG, and is supposedly temperature compensating. I think all that means is that it doesn't care what the ambient temp is, but I do as mentioned above, just wait a couple of minutes for the sample to cool off before reading.
I calibrate mine with a few drops of distilled water before each session. Not hard to do.

 

[good4whatAlesU]

Sounds like the same one we have at work Warra, except we use ours for measuring sugars in fruit (e.g. rockmelons and blueberries) a good piece of kit.
Our old one was a manual job, had to go outside into the light and look through it like a telescope to see a line, then take reading off an adjacent scale.

 

[ianh]

I use one of these
http://www.ebay.com.au/itm/RHB-18AT...ng-/182275684178?_trksid=p2385738.m2548.l4275
http://www.ebay.com.au/itm/RHB-18AT...ng-/182275684178?_trksid=p2385738.m2548.l4275
as I do not brew strong beers. Much easier to read than the 32Brix model. Also use a calculation for fermented samples plus have a 1 - 1.050 hydrometer to check results.

 

[Bridges]

I use a kegking one. They are still on their website. A purchase I don't regret at all. (compared with many I do)

 

[Danscraftbeer]

Yeah I think its worth repeating that calibration is the key before measuring every time! ! !
It only takes seconds to calibrate before every test through the days brewing.
Great little tool.

 

[nosco]

Ive been calibrating mine before use. Its always at zero. I stir the wort before before taking a reading and it still doesnt match my hydro. I have 2 hydro's and they both read the same. Its a brix SG refrac.

I have only just started using it again so I need to narrow down the difference a little more.

 

[Lowlyf]

How do you calibrate a refractometer??

 

[Mardoo]

If you have the below type of refractometer, there should be a calibration screw just behind the prism. In this photo the screw is underneath the little, round, black cap behind the prism. To calibrate, make sure the refractometer's prism and cover glass/plastic are clean. Get a small screwdriver that fits the calibration screw head. Put a few drops of distilled water on the prism and close the cover glass. Leave it for a couple minutes for the liquid and prism temperature to come to equilibrium. Look through the eyepiece. Using the screwdriver, adjust the calibration screw until the indicator line is exactly on zero on the measurement scale. Clean the refractometer. I've seen a couple refractometers that have an adjustment wheel instead of the cap covering the screw.

Ideally, you should calibrate using the same light you will use to take readings while brewing. Technically, I think you need to use sunlight, but a knowledgeable friend of mine said that using the same light will give you a consistent scale, and the difference will be miniscule.

If you have a digital refractometer, I can't help you

 

[Lowlyf]

If you have the below type of refractometer, there should be a calibration screw just behind the prism. In this photo the screw is underneath the little, round, black cap behind the prism. To calibrate, make sure the refractometer's prism and cover glass/plastic are clean. Get a small screwdriver that fits the calibration screw head. Put a few drops of distilled water on the prism and close the cover glass. Leave it for a couple minutes for the liquid and prism temperature to come to equilibrium. Look through the eyepiece. Using the screwdriver, adjust the calibration screw until the indicator line is exactly on zero on the measurement scale. Clean the refractometer. I've seen a couple refractometers that have an adjustment wheel instead of the cap covering the screw.

Ideally, you should calibrate using the same light you will use to take readings while brewing. Technically, I think you need to use sunlight, but a knowledgeable friend of mine said that using the same light will give you a consistent scale, and the difference will be miniscule.

If you have a digital refractometer, I can't help you

View attachment 106522

Nope that's the one I should be getting delivered today. Can you get distilled water from Woolies?