Refractometer

HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.

Help Support Homebrew Talk:

Shaneoco1981

Well-Known Member
Lifetime Supporter
Joined
Apr 4, 2011
Messages
581
Reaction score
12
Location
Rochester
Hey guys, I just got a refractometer in the mail with in the last couple of days. It's the kind that gives brix and specific gravity. I was bottling today and I decided to give it a try. It gave me a specific gravity of 1.026, which I thought was odd. I then used my hydrometer to get a "second opinion" and it gave me a specific gravity of 1.011. Does any one have any idea why it would be so off? P.s. I did use it on water and it gave me a specific gravity of 1.000.
 

JeepDiver

Well-Known Member
Joined
Apr 22, 2009
Messages
1,314
Reaction score
151
Location
Highlands Ranch
Refractometers are for pre-fermentation. There are some conversion formulas/tools you can use for once Fermentation has started. (Personally at that point I just use my hydrometer)
 

BendBrewer

Well-Known Member
Joined
Jan 26, 2010
Messages
3,126
Reaction score
81
Location
Bend
It's only accurate without calculations on unfermented liquid. You can use calculators and the OG to calculate the gravity on fermented beer and get close. Or use a hydrometer outside of brew day.

Sorry.

****edited as there is no such thing as unfermented beer.
 

BendBrewer

Well-Known Member
Joined
Jan 26, 2010
Messages
3,126
Reaction score
81
Location
Bend
Brewzor app for Smart phones has one. Under Brewing Calculators.
 

davel57

Well-Known Member
Joined
Feb 25, 2011
Messages
60
Reaction score
0
Location
Escondido
Google: [refractometer beer calculator] and you will find several. Not sure what formula any of them use.
 

bottlebomber

Well-Known Member
Joined
Apr 15, 2011
Messages
14,296
Reaction score
2,747
Location
Ukiah
Wait a minute, why aren't refractometers useful for checking FG? I just bought one and will be using it tomorrow :/
 

erikpete18

Well-Known Member
Joined
Apr 27, 2009
Messages
822
Reaction score
34
Location
Seattle
The alcohol in the beer throws off the reading so the light deflection isn't correct. So long as you know the OG, you can calculate pretty well what the FG would be. I know Austin Homebrew has an online calculator on their product page. However, I'd agree that its just easier to use a hydrometer for the FG, I've found its terribly difficult to try to drink the sample off the refractometer :D.
 

bottlebomber

Well-Known Member
Joined
Apr 15, 2011
Messages
14,296
Reaction score
2,747
Location
Ukiah
Because with alcohol in the solution, it's no longer a simple sugar and water solution - the alcohol changes the way the light is refracted.
Dammit why do I always find this stuff out AFTER I buy something... is there any way to compensate? Why the heck do they sell these things if it isn't useful through the whole process... *pissed*
 

ayoungrad

Well-Known Member
Joined
Sep 29, 2010
Messages
1,101
Reaction score
13
Location
Tampa
Dammit why do I always find this stuff out AFTER I buy something... is there any way to compensate? Why the heck do they sell these things if it isn't useful through the whole process... *pissed*
I got one knowing this. They are much better than hydrometers for checking gravities post mash/sparge and post boil. Quick, accurate at any temp and only a few drops are needed.
 

dantheman13

Well-Known Member
Lifetime Supporter
Joined
Mar 4, 2011
Messages
925
Reaction score
88
Location
Las Vegas
You can use refractometers to measure FG as well, as long as your beer is mostly attenuated. I just listened to two very informative podcasts on Basicbrewing.com. The first explains how to use a refractometer (and hyrdometer), and the second podcast is a followup with the same guest who has developed a new, supposedly more accurate formula for determining the FG (as accurate as a hydrometer):

Refractometers and Hydrometers

New Refractometer Formula

Here are the details of his results, and an easy to use spreadsheet tool for using his formula.
 

fckwalm

Pour me another beer!
Lifetime Supporter
Joined
Aug 31, 2010
Messages
52
Reaction score
0
Location
Montrose
brewhaha2057 ... i did this too... just ordered one and didnt realize... but didnt spend too much on it so not too upset (27 after shipping)
 

SpaceJunk

Active Member
Joined
Jan 31, 2011
Messages
27
Reaction score
3
Location
Silicon Valley
DeafSmith said:
Because with alcohol in the solution, it's no longer a simple sugar and water solution - the alcohol changes the way the light is refracted.
Interesting. I also recently bought this refractometer. I would assume however that you could still use it to check if fermentation is complete, as the reading would stay consistent?
 

emjay

Well-Known Member
Joined
Jan 7, 2011
Messages
12,771
Reaction score
1,716
Location
Toronto
SpaceJunk said:
Interesting. I also recently bought this refractometer. I would assume however that you could still use it to check if fermentation is complete, as the reading would stay consistent?
Yes. I don't even bother using a hydrometer until bottling time.
 
Top