I own a refractometer was told by the homebrew shop guy that refractometers are useless for homebrew, is this true? And does anyone know why? The obvious bonus for refractometers over hydrometers is not having to waste so much beer when taking gravity readings - a small pipettes worth versus 20-30mls in a tube. Thanks in advanced for your help!
They are useful for the reasons you stated. Consider finding a new LHBS. I guess he did not sell refractometers. Any reason why he thought that?
He probably meant that you can't just take the "gravity scale equivalent readings" from a refractometer and use them directly to compute ABV. The main reason is that the presence of alcohol changes the refractive index. But there are calculators out there that do the work of converting and adjusting for this. IMO, the best standalone refractometer calculator is Sean Terrill's. Also, his model is used (with slight tweaks) in BrewCipher.
Also, keep in mind that the refractometer is set to Brix, not to Specific Gravity. The dual scale refractometers (other than 2 new updated versions for brewing) have a bad scale for SG. You need to take the reading in Brix and then convert it using a proper calculator to SG. This is true for both pre and post fermentation.
That might be why the HBG (HomeBrew Guy) mentioned that - mine does have both markings - I did use it for cidermaking previously and it seemed accurate, but yeah I will give it a try with the Brix scale, thanks. Really? I had no idea this happened, thanks for the tip on Sean Terrill's calculator, I'll check it out.
Your LHB guy is way wrong. Refractometers, when used correctly, are a great instrument for determining SG and alcohol content, while using a fraction of the liquid required using a typical hydrometer. There are things that you must understand like the issue with alcohol and refraction as well as proper maintenance and calibration. I calibrate mine every time I use it because temperature changes can cause invalid measurements. They are excellent measurement devices for sugar content. Where they can go south is in the presence of alcohol, but there are a several smart folks who have helped make this a non issue. Here is a good article that describes what most have already said here: http://www.brewersfriend.com/2013/0...rrectly-for-maximum-accuracy-in-home-brewing/ Best of luck!
