Refractometer vs. hydrometer

[euge]

I have two hygrometers and a spectrometer. Here's the question:Using distilled water at 67 deg.  Hygrometer #1 reads 1.002 Hygrometer#2 reads dead on 1.000.But when I measured gravity of primary, I got #1 at 1.038, #2 at 1.032 and the spectrometer(calibrated to .000 with 67 deg distilled water) reads 1.050.I've tried cleaning the blue glass and the cover bue still get the  1.050. Since there is obviously some malfunction of the spec., would there be anything wrong with adjusting the spec to read 1.032 and frequently cross checking it's reading with the same hygrometer#2. I really do like the ease of using it, but knew something was wrong after 7 days of active fermentation only reading 1.050. Any suggestions?

Hydrometer. Refractometer.

[cash]

Thanks, I do remember reading that awhile ago. I'll have to do some reading on the adjustment for alcohol and gravity.So its refractometer during mash and hydrometer afterward.

[morticaixavier]

Thanks, I do remember reading that awhile ago. I'll have to do some reading on the adjustment for alcohol and gravity.So its refractometer during mash and hydrometer afterward.

you can use the refractometer for both you just have to make adjustments to the reading. Sean Terril has a spreadsheet that is apparently quite good for that purpose. I just use a hydro all the time cause I'm cheap.

[hokerer]

Sean Terril has a spreadsheet that is apparently quite good for that purpose.

Sean's actually now made it into a calculator on the web so you don't need the spreadsheet.  Just enter OG and FG from the refractometer and click "Calculate".  Here...

http://seanterrill.com/2012/01/06/refractometer-calculator/

[micsager]

Do you realize that you can't use the refractometer to read gravity after fermentation without making an adjustment based on the alcohol content?

OK, now I'm confused.  How can you know the amount of alcohol to make that adjustment, if you can't use the refractometer.

[tschmidlin]

Do you realize that you can't use the refractometer to read gravity after fermentation without making an adjustment based on the alcohol content?

OK, now I'm confused.  How can you know the amount of alcohol to make that adjustment, if you can't use the refractometer.

The adjustment as made based on the OG of the beer.

[micsager]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

[hokerer]

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Not exactly.  It's the presence of alcohol that messes up the reading.  The refractometer is fine with reading the sugar content in water (which is basically what wort is).  The problem comes in when there is also alcohol as it's refractive index is enough to mess up the readings.  So what you're really basing the adjustments on is the amount of alcohol present.  Knowing the OG just gives a good way to estimate that amount.

[tschmidlin]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Both alcohol and sugar have a non-zero refractive index.  In a mixture you can't tell how much is from one or the other.  Knowing the OG lets you solve the equation.  It is not as straightforward as knowing the % of each though, there are corrections that have to go into it.  This is why Sean's spreadsheet is good, it is based on results using fermented wort rather than the others which I suspect come from making mixtures of known sugar and alcohol concentrations and taking a reading.

[micsager]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Both alcohol and sugar have a non-zero refractive index.  In a mixture you can't tell how much is from one or the other.  Knowing the OG lets you solve the equation.  It is not as straightforward as knowing the % of each though, there are corrections that have to go into it.  This is why Sean's spreadsheet is good, it is based on results using fermented wort rather than the others which I suspect come from making mixtures of known sugar and alcohol concentrations and taking a reading.

Sounds way too complicated for me.  I'm gonna stick with a hydrometer.  Thanks for all the advice though. 

[euge]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Both alcohol and sugar have a non-zero refractive index.  In a mixture you can't tell how much is from one or the other.  Knowing the OG lets you solve the equation.  It is not as straightforward as knowing the % of each though, there are corrections that have to go into it.  This is why Sean's spreadsheet is good, it is based on results using fermented wort rather than the others which I suspect come from making mixtures of known sugar and alcohol concentrations and taking a reading.

Sounds way too complicated for me.  I'm gonna stick with a hydrometer.  Thanks for all the advice though. 

Awww don't give up!

It really isn't that complicated and Sean's alcohol % calculator is awesome. The refractometer is a great tool because all you need is a few drops of wort/beer to take a reading. Those of us that use a refractometer do it because of the simplicity and quick accuracy.

[tschmidlin]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Both alcohol and sugar have a non-zero refractive index.  In a mixture you can't tell how much is from one or the other.  Knowing the OG lets you solve the equation.  It is not as straightforward as knowing the % of each though, there are corrections that have to go into it.  This is why Sean's spreadsheet is good, it is based on results using fermented wort rather than the others which I suspect come from making mixtures of known sugar and alcohol concentrations and taking a reading.

Sounds way too complicated for me.  I'm gonna stick with a hydrometer.  Thanks for all the advice though. 

It's not complicated for you Mic, all you need to do is plug in your OG and SG and see what the calculator says.  It's the same with a hydrometer to get the ABV, you need the OG and SG.  Easy.

[morticaixavier]

Thanks Tom-

Would it be more accurate to say you adjust based on sugar content, rather than etoh content?

Both alcohol and sugar have a non-zero refractive index.  In a mixture you can't tell how much is from one or the other.  Knowing the OG lets you solve the equation.  It is not as straightforward as knowing the % of each though, there are corrections that have to go into it.  This is why Sean's spreadsheet is good, it is based on results using fermented wort rather than the others which I suspect come from making mixtures of known sugar and alcohol concentrations and taking a reading.

Sounds way too complicated for me.  I'm gonna stick with a hydrometer.  Thanks for all the advice though. 

Awww don't give up!

It really isn't that complicated and Sean's alcohol % calculator is awesome. The refractometer is a great tool because all you need is a few drops of wort/beer to take a reading. Those of us that use a refractometer do it because of the simplicity and quick accuracy.

besides if you are useing a hydro post fermentation you need to remember to de-gas the sample and then **shudder** you have to drink it. well okay you don't HAVE to drink it but you do have to de-gas it.

[bluesman]

It's not complicated for you Mic, all you need to do is plug in your OG and SG and see what the calculator says.  It's the same with a hydrometer to get the ABV, you need the OG and SG.  Easy.

I think you made it sound more confusing than it really is Tom.

...but I agree that it is easy.

Plug in the numbers and voila. 

[Al Equihua]

i only broke one hydrometer since i began brewing, year and 3 months, and finally purchased two weeks ago this one, got it in 50 bucks....

http://www.midwestsupplies.com/refractometer-atc-with-brix-and-sg-scale.html

any comments? so if i got ir right in this one, do i have to make compensations in a chart depending the temperature of the sample?

pd im planning making some wine also this summer,thats why