[psuskp]

I broke my hydrometer (again), and I was thinking of replacing it with a refractometer. Is it worth it? There seems to be a wide range of prices. How much do I need to spend?

[Slowbrew]

I got one on eBay for $50 or so. 

I really like the convenience of using a refractometer.  Make sure your get one that is ATC.  Automatic Temp Compensation (I think that's what it stands for) allows you to use the refractometer through out a range of air temps.  It does not have to do with wort temp so make sure to let your sample cool a bit before taking a reading. 

There are good conversion spreadsheets on the web that allow you to take readings in any phase of the fermentation process.

Paul

[blatz]

just like the wide range of prices, you'll find a wide range of opinions of whether people like them or not.

I spent <$25 on ebay and have been using mine for years now - its great and really helps for during the brewing process readings - I can more easily take a midboil reading and know if I am on target for my planned OG or if it looks like I am going to be off, I can either fix it or adjust my hop schedule on the fly.

That to me is invaluable.

I also use it to take FG readings, but you need to use an adjustment for the alcohol in solution (Sean Terrill has a good link in his signature - screen name a10t2) or Beersmith has a good one as well.

[blatz]

I guess guys named Paul tend to think alike 

[narvin]

I would suggest having both.  I love my refractometer, but I like to occasionally check against a hydrometer.

I use the refractometer for FG readings during and after fermentation (as well as measuring commercial beers - you can back-compute OG and FG based on the abv they advertise). It's incredibly easy to use without losing a bunch of beer.  Sean's spreadsheet is more accurate than the tools you see in ProMash or online, which always measure low in my experience.  I had previously found that adding about 0.5 brix to your reading was a rough swag that made the FG calculators a lot closer.

[cenosillica]

I would recommend having both. Your hydrometer will be able to accurately check your FG. A refractometer does not accurately read FG when there is alcohol present, you have to make a rough adjustment to compensate or find an online conversion tool. Therefore, I prefer to use a refractometer on brew day and as the fermentation progresses, I use the hydrometer. Occasionally, I use both to make sure my calibrations are in line with each tool.

[bluesman]

Another vote for both. They both have their place in the brewhouse and cellar. I use my refractometer on the front end of the process and the hydrometer for measuring gravity of finished beer. Both are a must have for me, and a worthwhile investment as well

[pehlman]

I like that concept of using the refractometer on brew day and the hydrometer on the tail end of fermentaion. I've broken a few hydrometers and I think a refractometer is going to be my next piece of equipment.

[Malticulous]

I hate mine. It always 2-10 point off from my hydrometer. It useless to me.

[beerprof]

I hate mine. It always 2-10 point off from my hydrometer. It useless to me.

Have you calibrated it? It should not be 2 - 10 points off.

[tygo]

I hate mine. It always 2-10 point off from my hydrometer. It useless to me.

Have you calibrated it? It should not be 2 - 10 points off.

+1

I had a lot of problems with getting mine to read correctly to the point where I was thinking it was a useless piece of junk.  But thanks to some help from some folks here I now have it to the point where I feel like I can rely on it (almost) as much as I do my hydrometer, at least on the hot side.

The keys for me were calibrating it before each use at the ambient temperature I was using it at, reading it on the brix scale (mine is a dual scale), and reducing the brix reading I do get by 4%.  Since I've done those things my refractometer readings and hydrometer readings usually agree to within 0.001 SG.

[Malticulous]

I calibrated it they day I got it at room temp. It was about $30 on ebay from Hong Kong.

I searched and found I'm not alone with the problem. Both the hydrometer and refractomerter or designed for sucrose. Beer is a complex blend of sugars that will refract differently.

[a10t2]

Beer is a complex blend of sugars that will refract differently.

Granted, but with the appropriate corrections the hydrometer and refractometer should still agree within a point or two for both OG and FG. If you can't get that kind of agreement, and they've both been calibrated properly, then I'd bet one or the other is defective.

[Malticulous]

What are the appropriate corrections?

[a10t2]

What are the appropriate corrections?

http://seanterrill.com/2010/06/11/refractometer-estimates-of-final-gravity/
http://seanterrill.com/2010/07/20/toward-a-better-refractometer-correlation/
http://seanterrill.com/2011/04/07/refractometer-fg-results/

The first post gives some basic methodology, and the most recent FG corrections are in the last post.