Refractometer

[Georgedgerton]

Hi guys, just a bit of advice about buying a refractometer. Is there much of a difference from the cheaper ones to the slightly more expensive. I noticed one that was fairly cheap (about $40) said that it had automatic temperature compensation. Any constructive guidance would be appreciated.

 

[Sugar89]

I picked one up from Keg King about a year ago ($50) it has ATC as well, seem to work well. I still use a hydrometer as well because initially I was a bit confused because I was getting such a big variance between my ref and Hyd readings during fermentation, then I found out Ref readings are only accurate for unfermented wort... but there are calculators available to help adjust those readings.

 

[Wobbly74]

I think you'll find the atc = a small drop of wort on a much larger lump of alloy & glass which will quickly equalise the temperature...

 

[Georgedgerton]

Thought as much; thanks for your replies

 

[Mr B]

Wobbly is right, but also keep in mind that they need to be calibrated each time before use.

I think that the reason for this is that the temp of the actual refractometer influences the readings, so you ‘zero’ it with plain or distilled water before a brew so you get an accurate wort reading.

 

[Wobbly74]

On calibration, it might be worth calibrating at a higher, known gravity as well. Both my refractometer and my hydrometer are spot on at 1.000 but are out by 2 points at about 060. Which one is right is anyone's guess, so it's something I'll need to get around doing with some dissolved dme and water by weight at some point.

 

[RobinW]

I'm getting some work done on my pool next week.
The pool guy told me my refractometer can measure the salt concentration in the pool.
Still searching for details on that one but it looks like .77 to 1.03 Brix is correct for a salt pool.
A tool of many talents by the looks.

 

[peterlonz]

A wee bit off topic - advice was requested.
Reading a hydrometer is tricky enough as it is.
A refractometer just introduces more variables & opportunities to get things terribly wrong.

 

[Georgedgerton]

Sorry I haven't replied earlier but had an unexpected trip on business.
I take it from peterlonz that he would rather not use one? Thanks for your interest

 

[RobinW]

I bought a $15 one off eBay from honkers and it works fine.
Mine only shows Brix but if measuring fermenting wort you have to apply a correction factor if there's alcohol in the wort anyway.
I use the refractometer tool in Beersmith and once calibrated to suit my refractometer it is close enough for me.
It's great for measuring pre/post boil SG and testing to see if fermentation has stopped/finished.
You only need a few drops to test, not a hydrometer tube full.

A couple of times measurements didn't seem right but comparing it to a hydrometer proved the figures where in fact true.
There's a place for both tools in the kit. And now I can test my pool salt too. Excellent.

 

[MHB]

On calibration, it might be worth calibrating at a higher, known gravity as well. Both my refractometer and my hydrometer are spot on at 1.000 but are out by 2 points at about 060. Which one is right is anyone's guess, so it's something I'll need to get around doing with some dissolved dme and water by weight at some point.

Use Sugar (Sucrose), the SG, oP (Plato) and oB (Brix) scales are all done in sucrose water standards (well not the SG so much, that's derived but the conversions between all three scales are) Brix and Plato are the same scale, Plato is just newer and more accurate (in the 4-5th decimal), both supersede the even older Balling. All are defined as the density of a %W/W Sucrose solution (W/W being weight to weight i.e. 10oP 100g of sucrose and 900g water to make 1,000, or 10% sucrose).
Using wort or DME... will introduce errors that will actually compound the errors rather than reducing them.
Some good resources for stepping between the various ways of measuring wort are available here ACBC Methods of Analysis
Mark

 

[Wobbly74]

Thanks Mark - good to know.

 

[tugger]

My 2c.
I have found the optical ones are more reliable than digital ones.

 

[gaijin]

I use an optical refractometer with automatic temperature compensation https://hoppydaysbrewingsupplies.com.au/product/refreactometer-brix-sg/

I haven't checked it against a hydrometer since I first picked it up, but have found it accurate enough for my use (+/- 0.2%abv). I would recommend for $55, but if you want something highly accurate, most people seem go for the simple hydrometer.

 

[Crimson Cadaver]

If only I could get more light into my refrac. Problems of brewing inside with dim lighting solved haaa