refractometer question?

I just got my refractometer (the AHS sale...) and it has SG on it (no need for brix conversion)...

My question is this, what adjustments do i make for the "wort correction". everything I am reading deals with brix???

sorry, just a little confused...

thanks

goose1873 said:

I just got my refractometer (the AHS sale...) and it has SG on it (no need for brix conversion)...

My question is this, what adjustments do i make for the "wort correction". everything I am reading deals with brix???

sorry, just a little confused...

thanks

Click to expand...

Do you mean the correction for the alcohol once fermentation is underway?!?!

Is this the one you bought. It should have brix and SG on it.

http://www.austinhomebrew.com/popup_product_images.php?pID=12574

yes. everything I am reading says that you still need to make a brewhouse correction because they are not intended to calc. maltose...

can I just read it directly (assuming I wait 60sec for temp to regulate)?

You can read it directly to get OG or Pre-boil gravity. For checking gravities once you are fermenting, you need to plug it into a calculater with the measured OG to get the current gravity reading. If you have beersmith, its in there. There are also webpages with it...my fav: http://www.onebeer.net/refractometer.shtml

If you go to the item on the AHS website it calculates it for you. It has a box to put OG and FG. It then calculates real FG, alcohol by vol % and alcohol by weight %.

goose1873 said:

yes. everything I am reading says that you still need to make a brewhouse correction because they are not intended to calc. maltose...

can I just read it directly (assuming I wait 60sec for temp to regulate)?

Click to expand...

The best thing to do is test the SG reading on unfermented wort vs. your hydrometer a few times and see if a conversion is required. You are correct that the typical Brix refractometer is not calibrated for maltose and a minor adjustment is necessary between Brix & Plato/SG. This chart is handy:

http://beerbarons.org/pdf/brewingCheatSheets/refractometerBrixToSGConvertion.pdf

But again, IMO the best approach is to test your refractometer at different gravities.

Cheers,
Glenn

Thanks for the replys. I think I have it now. One last question...why when I look into the refractometer:

http://www.austinhomebrew.com/popup_product_images.php?pID=12574

as you can see the charts are side by side...why do they not correlate to the conversion table? i.e. 20 Brix is across/= ~1.077SG and on the chart:

http://www.onebeer.net/refractometer.shtml

20 Brix = 1.083 ????? it does not match up across the board...

thanks again in advance!

bobbyM has a nice video on how to use the refract and compares it to his hydro. Nice video.

Good question. I just checked a bunch of calculators online and beer smith and they were all between 1.081 and 1.083. So the AHS one seems to be reading a little low on SG at first grin.

I decided to use this one:
http://seanterrill.com/2010/06/11/refractometer-estimates-of-final-gravity/

He goes into the typical formula and its margin of error. Then proceeds to work out a better formula with a much smaller error margin.