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We were in the market for a digital refractometer - as we find regular floating hydrometers cumbersome and wasteful in terms of the amount of fluid required to take a sample, and came across this relatively cheap option from AliExpress. Read on to find out what it's like.
Introduction
Initially we were looking at a handheld 'telescope' style refractometer, but our research suggested that these were inaccurate and unreliable, to the point that correction charts need to be calculated and maintained in order to get any sort of accuracy when using them. Check out this video from Flora Brewing on YouTube to see what is involved in doing this. Needless to say, this is not something we were willing to do - we're looking for ways to make our brewing days and processes easier and more straightforward, not more complex and convoluted so we started looking at options for digital refractometers.
Cost Effectiveness
As you'd expect, digital refractometers are a significant price jump from the previously mentioned handheld refractometers. After some research though we discovered that some digital refractometers can be found on AliExpress at a price point somewhere between the handheld ones and the digital ones available from other online stores.
Purchasing from AliExpress
The one we found looks just like this one from Fruugo which at the time of writing this article, was on sale for $289. We were able to purchase one from the "Soonda Goodfaith Store" on AliExpress for around AU$118 including delivery. If you're in the market for one, make sure you get one that reads Brix or Specific Gravity as these are the scales generally used for brewing.
No doubt if we post a link directly to the item on the AliExpress website, the link will eventually break, so here's a screenshot of the actual advertisement for the one we purchased.
We know buying from AliExpress can be a little hit and miss - but certainly in some cases bargains can be had for seemingly identical products at a fraction of the cost of those sold in regular retail or other online stores. We wanted to take the gamble so took a punt on buying one from AliExpress.
Fast Shipping
As expected when buying from AliExpress, shipping was from overseas but was surprisingly prompt.
First Impressions
It arrived in a nice plastic hardcase, however the plastic clips to secure the case are just folded plastic so will no doubt snap off in due course after being open and shut many times.
Inside the hard case is the actual refractometer, a plastic pipette for drawing samples, a screw driver for removing the battery cover, as well as a microfibre cloth for cleaning the lens. The refractometer requires a single AAA battery which isn't included.
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| The digital refractometer is powered by a single AAA battery |
Initial Testing
We performed an initial accuracy test by testing a sample directly from our latest All Inn Brewing Co fresh wort kit - which has been stamped with a gravity of 1.060
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| Our fresh wort kit used for initial accuracy testing of the digital refractometer |
Straight out of the box without running any calibration, we had a reading of 1.068 - 8 points higher than the specific gravity of our wort at 1.060
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| Initial testing was 8 points higher than it should have been |
This was using 3-4 drops onto the refractometer for analysis. After changing to only using 2 drops, we got a reading of 1.059 - much closer to our expected reading.
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| Second test was much more accurate - within 1 gravity point |
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| Calibrated and tested using water for a reading of 1.000 |
Our next reading of the wort was now a whopping 1.076 - 16 points higher than the known value. Obviously the calibration threw everything way out, so we ran a calibration again using distilled/spring water instead.
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| Second test after calibration was 16 points higher than expected |
After running a calibration again using distilled/spring water, we were able to get some more consistent readings of around 1.062 and 1.063, which was still 2-3 gravity points higher than expected
Sample Volume
We did find it interesting that the volume of sample (ie. number of drops) placed onto the lens of the refractometer seemed to affect the readings. Using 2 drops seemed to give the best results, with using more than 2 drops causing a reading significantly higher.
Admittedly we've only tested the accuracy of this unit against a single sample with a gravity of 1.060. We plan on doing some further testing of samples with differing gravities and will compare the results against a regular floating hydrometer. It's possible that lower gravity samples may be more accurate.
Conclusion
After several years of use we're pretty happy with this digital refractometer. The readings are generally accurate and within the expected range, and we more often than not check against a regular floating hydrometer just to make sure. There is the occasional reading that's a bit off by a few (or more) points but these are the exception rather than the norm.
We only brew once every month or so, but still haven't had to change the single AAA battery after several years of use.
In our opinion, this digital refractometer is a decent compromise between a floating hydrometer and the high-end digital refractometers available on the market. We'd recommend regularly checking your readings against a floating hydrometer just to be sure what it's reading is accurate though and don't solely rely on it.
Check out the results of our further testing and comparison between this digital refractometer and our floating hydrometer.
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