Using a Refractometer

[Jus]

Howdy

I need a bit of help using my new refractometer. I kinda thought it would be easy but its turning out to be a bit of a struggle. My 4.5 % beers are showing up as 14% . I tried some wine which also showed up a fair % higher, and also got about 5% higher on some rum. Despite my attemps at calibration i cant seem to fix this

The model i have measures in % alcohol, in inrements of 1%, and it goes up to 80% (not ideal for beer i know, but it was a present so i'm not going to complain). There is no automatic temberature control/correction.

The instructions leave a lot to be desired, thus i made a lot of assumptions when i used it.

My questions are:
1. The readings are based on 20 degrees. I assume this is liquid temperature rather than room?
2. I calibrated by putting some distilled water on the lens for 30 seconds and made sure % was set to zero. I assumed if the temperature of the distilled water and the alcohol were the same, that i would get a true reading and not need to correct for any temperature variance. Is this correct?
3. Am i better off doing this in full natural sunlight? My readings were the same in flourescent light and later afternoon.
4. ANy more tips???

Cheers
Jus

[drsmurto]

refractometer that measures in % alcohol....interesting.....

are you 100% sure? I have this one. My understanding and from my limited experience a refractometer is good for unfermented wort but becomes more difficult to relate back from degrees brix to SG once alcohol appears. I use the refractometer on brew day and my trusty 10 year old hydrometer from then on.

[Jus]

yep, 100% sure, here is an example of what im talking about http://www.bacto.com.au/refractometers.htm - see about half way down the page under "grape juice & wine refractometer"

[drsmurto]

No offence Jus, but i reckon they are pretty much the same except for the readings.

The problem you will have is that they are very small and the difference between 0 and 80% alcohol is pretty bloody huge. The difference between 4.5% and 15 % is a few mm on that scale and you are a better man than me if you can pick that with 100% confidence.

My 2 c - nice idea but go back to the hydro.

I use a refractometer as a basic check to see how the mash, sparge and boil are going to see if i am hitting targets.