[hairyhood]

I am using a automatic temperature adjusting refractometer to compute my gravities.  I have not been using a hydrometer at all.  I do not know for sure what it shows on DISTILLED water, but I know that on tap water it shows exactly zero.

Any thoughts on this?

[tygo]

I am using a automatic temperature adjusting refractometer to compute my gravities.  I have not been using a hydrometer at all.  I do not know for sure what it shows on DISTILLED water, but I know that on tap water it shows exactly zero.

Any thoughts on this?

I don't have a definitive answer on this except to say that I've been playing around with my ATC Refractometer quite a bit lately in parallel with using the hydrometer to take readings.  And based on those tests I don't completely trust the refractometer.  The readings are close, usually within 0.003, but different (the refractometer usually reads high).

That being said I wouldn't care about that much of a difference in gravity for a starter so you should be fine as far as that goes.

[Hokerer]

I am using a automatic temperature adjusting refractometer to compute my gravities.  I have not been using a hydrometer at all.  I do not know for sure what it shows on DISTILLED water, but I know that on tap water it shows exactly zero.

Any thoughts on this?

Aren't refractometers inaccurate once there's alcohol present?  If I remember correctly, there's some sort of manual correction that you can do but I'm not sure.

[tygo]

Aren't refractometers inaccurate once there's alcohol present?  If I remember correctly, there's some sort of manual correction that you can do but I'm not sure.

Yeah, there's a correction you have to do once fermentation has begun and alcohol is present.  I don't know the formula off the top of my head.  I just usually use the tool in Beersmith.

[denny]

Aren't refractometers inaccurate once there's alcohol present?  If I remember correctly, there's some sort of manual correction that you can do but I'm not sure.

Yeah, there's a correction you have to do once fermentation has begun and alcohol is present.  I don't know the formula off the top of my head.  I just usually use the tool in Beersmith.

That was my thought as soon as I saw he was using a refractometer.  I'd bet he's not using the correction.

[theDarkSide]

Here's a link to the Morebeer site that has an excel document:

http://morebeer.com/learn_vids/vids_refract

[tschmidlin]

That was my thought as soon as I saw he was using a refractometer.  I'd bet he's not using the correction.

I'll bet you're right Denny.

You know there's a formula you have to use to convert the refractometer reading to gravity, right?  It's straightforward when it's just sugar in the solution, but when there is ethanol you have to account for it.  You need the original and current brix readings, then plug them into the spreadsheet just posted.

I've found the spreadsheet to be inaccurate when compared to hydrometer readings, but it's better than nothing.  It should get you within a few points of what the hydrometer would read.

[tschmidlin]

When I say "not finishing".....I have an IPA recipe that calls for an OG of 1.064 and an FG of 1.014.  I started at 1.066....and have been stuck at 1.035.

Just so you know, I converted your numbers to brix (1.066=16.5, 1.035=8.75) and plugged them into the spreadsheet.  It says your FG is 1.0155.  My experience is that it will actually be a couple of points higher than that, but I'm sure it will be fine.  That is reasonable attenuation for an extract batch.

[hairyhood]

Interesting.  I was not aware of having to worry about the alcohol.  I always get my brix reading and go to this page to get a conversion.    http://www.fermsoft.com/gravbrix.php

I also plug it into Promash and I get the same results.  So, my FG showed on my refractometer as just below 9....which, according to the chart would come in as 1.036-1.035.  So you think that even the reading in Promash is incorrect?  If the FG is really 1.0155 then I have hit my target.

[Hokerer]

Interesting.  I was not aware of having to worry about the alcohol.  I always get my brix reading and go to this page to get a conversion.    http://www.fermsoft.com/gravbrix.php

I also plug it into Promash and I get the same results.  So, my FG showed on my refractometer as just below 9....which, according to the chart would come in as 1.036-1.035.  So you think that even the reading in Promash is incorrect?  If the FG is really 1.0155 then I have hit my target.

Yes, that conversion table is not "alcohol corrected" nor is the ProMash conversion.  Plug your numbers into the earlier referenced MoreBeer spreadsheet and watch what happens.

[hairyhood]

Well, according to this new-found (to me) conversion....I am almost on my target.  I guess that I have learned that I need to keep doing the starters, take both a hydrometer and refractometer reading....and....go ahead and keg my beer!

Thanks to everyone who had ideas on this problem.  I have been out of brewing for a while now.  It is nice to get back into it and have some people to bounce things off of.  Again, I greatly appreciate everyone's input.

[tschmidlin]

Interesting.  I was not aware of having to worry about the alcohol.

Take a reading of some vodka with your refractometer and you'll see that it has an affect.  It's less than a similar % mixture of sugar, but it's not 0.

The only way to correct for the alcohol is to have both an OG and SG reading, otherwise there's no way to know if your reading of 8 brix is a 1.032 OG beer or something that started at 18 brix and fermented down.  Well, the taste will tell you if you know those are the only two options, but that's beside the point

[hairyhood]

At this point I am just glad that my beer is closer than I thought.  I have 3 carboys ready to keg....I am eager to drink.  I need a few more extract batches to work out the kinks and then I am back to the all-grain.  Thanks again!   

[maxieboy]

I am using a automatic temperature adjusting refractometer to compute my gravities.  I have not been using a hydrometer at all.  I do not know for sure what it shows on DISTILLED water, but I know that on tap water it shows exactly zero.

Any thoughts on this?

Aren't refractometers inaccurate once there's alcohol present?  If I remember correctly, there's some sort of manual correction that you can do but I'm not sure.

Yup. I use a refractometer on brewday. So convenient. Hydrometer from then on.

[abraxas]

Also..you can easily get rid of the chlorine in your water with a little potassium metabisulfite (campden tablets).  One 1/2 gram tablet will treat 20 gallons of water, just break a tablet into an appropriate sized section and throw it in, the reaction is very quick and the heating process should drive off the sulfites to prevent any possible reaction with the yeast.  This is especially important if you have chloramine in your water.

You can feel good, good, good about hood.