Fractometer vs Glass Hydrometer

[keyman]

I just bought a new fractometer for around $28. I am to the FG part of my brew and I keep getting a reading around 1.025. thinking I needed more time for fermentation I waited several days and Dah! I decided to check it with my glass Hydrometer. I got 1.010 with booth of my glass meters. This either tells me the fractometer is junk or I am not doing something right. I did the calibration according to the instructions using distilled water. I tried sever more test's and got the same reading. Any Ideas?

 

[hunter_le five]

The presence of alcohol distorts a refractometer's reading. It is not defective, just a shortcoming inherent to the design.

The general rule of thumb is use a refractometer for everything BEFORE pitching yeast, and a hydrometer after.

There are calculators that can be used to "convert" refractometer readings post-fermentation, but I have never found them to be reliable. Others will swear otherwise, so take that for what it's worth.

 

[Kingbogart]

I'm going to assume there is a typo, and you have purchased a refractometer.

Refractrometers do not work well with the presence of alcohol. There are some calculators out there that will convert your refractometer final reading into a specific gravity reading but they don't always work very well. In general, refractometer pre fermentation, hydrometer post fermentation.

 

[flars]

Refractometers are not accurate in the presence of alcohol. There are on line converters, but the hydrometer is still more reliable for FG.

 

[keyman]

Thanks guy's I will us the glass hydrometer after fermentation. Didn't know this little factor...