anyone successfully use refractometers & hydrometers?

[Michelle]

I'm trying to measure alcohol and sugar content for commercial production and would like to do it on a regular basis for QC and not have to get lab testing every time. 

I've read that refractometers and hydrometers may not be accurate for kombucha and wondering if anyone has experience with either. If either tool is consistently over or under compared to lab testing, that's great since I can get a sense for where the brew is. But they could be give random readings and not be helpful at all.

I do have a finishing hydrometer but it floats too high so I need to find the right range. I haven't invested in a refractometer yet, but would like to if they're work for reading sugar in kombucha. 

[Jared Englund]

We are able to use a hydrometer and measure pH to accurately estimate alcohol content.  Now we just send samples in every once in a while to make sure we are staying on point.

[Michelle]

What range is your hydrometer? So far, my hydrometers either sink or float too high so haven't found one in the right range.

[Jared Englund]

Ours ranges from 0 to about 1.020.  It's made for bottling and we like it because we are working with such low sugar amounts.
It sounds like you may have sweeter booch so a thicker hydrometer would work better.  I have measured Kombucha of other brands up to 1.050!  That was the finished product!  (can someone say bottle bomb?....)

[Michelle]

I finally figured out right hydrometer to use. Wow, 1.05 is up there! I've read that hydrometer readings for kombucha will result in a higher ABV than is actually present and you should halve the ABV. Jared is that your experience as well or do you find that you get similar results to lab testing.

Thanks!

[Jared Englund]

Yes that is a decent rule of thumb so long as your culture is fairly healthy.  If your bacteria culture is strong, it will eat up more of the alcohol that was created.  You can measure that by how the culture drops the pH.  The more of a pH drop, the more alcohol was eaten up however pH is not linear.  I do believe there is a formula that could be created, however we are just looking at all of our test results and using that to estimate.