Precision Hydrometer, Cool a New Toy!Friday, March 8th, 2013
A precision hydrometer is a fun upgrade and only runs about $15. Yeah, taking measurements, entering brew logs, and doing brewing science – this is fun!
I’ve broken a few hydrometers on accident over the years and normally bought the cheap ones that read from 1.00 to 1.16. These are all purpose models meant for beer and wine makers. An SG of 1.16 is approximately 36 Brix, which would be 24.9% ABV! The recipe calculator can handle a beer that strong, but I don’t think I’d enjoy 5 gallons of 50 proof beer.
With a scale that reads up to 1.070 (~17 Plato) this precision hydrometer is fine for most beers. The reduced range makes it is easier to read and provides a higher level of accuracy. I checked my records, and out of all the batches I’ve brewed, only a handful are above an OG of 1.070. I still have the old one as a backup for the next time I brew a barely wine or an IIPA. Even so, this would be my go to hydrometer for measuring FG. The flute is narrow and the glass is delicate, so instead of banging this one around, I hand dry it and put it back in the plastic case it came in each time I use it.
Here they are floating in water for comparison.
There are four important factors to be aware of in order to take an accurate hydrometer measurement:
- The temperature the hydrometer is calibrated to (usually ~60F / 68F, ~15.5C / 20C). Only at the calibration temperature does the hydrometer read true.
- The temperature of the sample. The hotter the sample, the lower the instrument will read. For example, a reading of 1.040 at 100F would really be 1.044 on a hydrometer calibrated to 68F, and 1.046 for one calibrated to 60F. Always let the sample cool down before handling it or letting it touch the delicate glass. I prefer to wait until it is around 80F.
- The offset for the hydrometer. In theory it should be zero, but with a cheap one you never know. We have a post on how to check if your hydrometer is correctly calibrated.
- Also, make sure your thermometer is calibrated correctly.
The Brewer’s Friend Hydrometer Temperature Correction Calculator adjusts for the temperature of the sample and the hydrometer calibration. This is also built into the brew log entry screen under the brew feature. The hydrometer calibration, and its offset (#1 and #3) can be stored in your Brewer’s Friend account profile. These values automatically slot into the brew log entry screen when you record gravity measurements.
Taking this a step further:
There are precision hydrometers kits out there that contain multiple instruments – one for measuring the OG and another for the FG.
This model is a good intermediate upgrade, and may be my last – if I don’t break it on accident!
Post by Larry