Is the calibration technically off for Specific Gravity? Yes but this is intentional.
Refractometers are intended to work with clear liquids so you must calibrate them to work with beer wort. To learn more, please Google Refractometer calibration, specifically you may want to read the comments on BeerSmith software and its forums. I use BeerSmith for brewing and it has a special tool just for Refractometer calibration to convert Brix to Specific Gravity. After performing the calibration, it confirmed the Specific Gravity scale on the Refractometer was exact for Unfermented Wort.
That last statement is important, however, it is only accurate for UNFERMENTED WORT. Once the wort is fermented you must use the Brix scale and perform the appropriate calculations to convert back to Specific Gravity. Once again, BeerSmith does this beautifully.
Finally about this Refractometer. Nothing could be easier to use. Calibrated it the first time with distilled water (mine required no adjustment, perfect out of the box). Then calibrate with unfermented wort you know the Specific Gravity (use a Hydrometer). After calibration is complete, just a couple of drops on the glass and you instantly have a reading. The calibration process is only required once, unless you drop it or something then you may want to check again.
The reading couldn't be easier either, it is a bright blue line across the viewer and the viewer has a focus adjustment to ensure you can easily read the scale.
| Brand | Ade Advanced Optics |
|---|---|
| Manufacturer | Ade Advanced Optics |
| Model number | BCBI9177 |
| Part Number | BCBI9177 |
| Number Of Items | 1 |
| Batteries Included | No |
| Batteries Required | No |
| Material Type | Aluminum body with optic lens |
| Manufacturer | Ade Advanced Optics |
| Item model number | BCBI9177 |
| Product Dimensions | 20.07 x 6.86 x 5.84 cm; 19.84 Grams |
| ASIN | B00AOCKWMU |
