Refractometer

I am thinking of investing in a refractometer to use in the brewing process. I've read that you can take samples during brew day to get your OG in the right place. I've read that you can use DME to get your specific gravity to where it needs to be. For example, if your OG is going to be too low you can add some DME to the wort to bring the OG up. How do you know how much DME to add or is the method to just add a little at a time while keeping testing on the refractometer?

Ideally you would know your eff. and youd be within a couple points of target SG anyhow.

You could boil longer

Or you can input the recipe into a brewing software to determine how much DME you need to reach your target, from where you are.

If you add 1 pound of DME to 5 gallons of wort, it will raise the SG by about 9 points per Pro Mash.

Refractometers are very handy. I like mine for being able to take a gravity from a few drops without waiting forever for it to cool.

As for adding DME to help hit your proper OG, it is a relatively simple calculation but I don't do it myself. I recommend beersmith software, but there are free brewing calculators on websites.

I think one of the best things you can do with a meter is read the pre-boil gravity. This way, if you know you are high or low (and that you've hit your volumes). If you come in high you know you boil less and if you are low you can boil more. The great thing is that you can then continue to test when you start to get to the end of your boil. Several times i've realized my boil was too aggressive, so i knew to add some water to bring my gravity down while still having 5.5 gallons in the bucket. I also can tell if i need to raise my boil to get rid of more water in the remaining minutes to boil off some water to hit my OG.

I'm sure you can add DME, but if you hit the right volume of wort, then the meter gives you a great sense of where you stand at the end and you can usually adjust to finish on your numbers.

Do use software? If you use something like beersmith it is very easy to figure out how much to add.

You simply take the reading and determine how many points off you are. If you add DME to the recipe in beersmith it will tell you how many points it adds.

If you don't use software, download beersmith and try it. It's free for a month, and well worth the $25 afterwards.

For me, a refract is a must have for brewing. It allows you to make adjustments on the fly and as posted before, no more waiting for it to cool down.

Lets say your brewing and your take a refract reading at the end of the mash (OG) and you want to know what your SG will be after you boil.
Lets assume you had 8 gallons of runoff and your reading was 1.038. At the end of the boil you want to have 5.5 gallons of wort. (38x8)/5.5=55.3 or 1.055 Now you say to yourself, dang, I needed it to be 1.063 I'm 8 points short. Well we know that DME=45points per lb. & LME=38points per lb. but lets use DME for this example. (63-55)/45= .18 lbs of DME

Now I personally don't worry that much about ending up short, I just roll with what ever my system kicks out that day. I only use that DME I have around for makeing up starters or mixing it with icecream to make malted milk shakes!!

Snafu said:

I just roll with what ever my system kicks out that day.

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+1. I don't even take a pre-boil gravity anymore unless I'm using some unusual technique like partigyle, or just brewing a huge beer. My system has shown reliable efficiency to the point that I know it will be within a couple of points and I'll just accept it for what it is. I still dig the refractometer though.

I don't recommend this tool, it is too inacurate. Mine lies deep in the drawer, I use it only occasionaly, for more coarse measurements.

You can spend the money better.

I will be using a top'o'the line refractometer form work this weekend. It's one of those fancy digital refractometers that cost $600. I'm planning to do a check of my brewing efficiency and the thing is deadly accurate. After that, I don't really think a refractometer's necessary, the hydrometer works fine. I have been blindly going along making beer that tastes good with no idea of PH or SG. I guess, I just trust in Beersmith and follow the recipe.

Piotr said:

I don't recommend this tool, it is too inacurate. Mine lies deep in the drawer, I use it only occasionaly, for more coarse measurements.

You can spend the money better.

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I don't agree. mine is dead nuts on with hydrometer

I agree, refractometers are extremely accurate when used properly.

#1 you have to calibrate it with distilled water
#2 you have to determine the correction factor to get Plato, mine is 1.054, but this number varies.

Once you do those two things, they are dead accurate, especially if you have an ATC refractometer that compensates for temp. automatically.

Great to check preboil, during boil, post boil, during fermentation and FG... they are amazing tools.

springer said:

I don't agree. mine is dead nuts on with hydrometer

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+1 here as well, but I admit I only use it when I want to take a reading on hot wort, once cooled its hydrometer all the way.

Snafu said:

+1 here as well, but I admit I only use it when I want to take a reading on hot wort, once cooled its hydrometer all the way.

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Why so?...

just personal preference. Plus it lets me get in a taste!

I'm considering getting one for pre-boil measurements. I'm usually running around for most of the brew session and letting the wort cool, then making the temp correction, for the hydrometer is one of the more annoying aspects. I'd probably use it post-boil, too, but for me the value is in quick measurements pre-boil.

Anyone have a recommendation for a quality, reasonably priced unit?

JKoravos said:

I'm considering getting one for pre-boil measurements. I'm usually running around for most of the brew session and letting the wort cool, then making the temp correction, for the hydrometer is one of the more annoying aspects. I'd probably use it post-boil, too, but for me the value is in quick measurements pre-boil.

Anyone have a recommendation for a quality, reasonably priced unit?

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You can find 20 vendors on Ebay with great feedback selling them for $30 or so shipped. Everyone I know, bought them there, and they are happy with thiers as well.
My LHBS is selling thiers for $80.. BWAHAHAHAH

Yeah my wife knew I wanted one so she got me one from the LHBS. Oh well, supporting the local economy...

I think wanting to be able to compensate for a missed preboil gravity and wanting a refractometer are two different things. I love my refractometer; I hardly waste any beer now. Granted, I don't get to taste it until it's in the keg, but I'm okay with waiting.

I'd like more clarification on how they're supposed to be less accurate. Corrects for temperature and isn't influenced by bubbles in the tube/wort...

I love my refractometer! I use it for everything now. I only use my hyrdo to measure my initial gravity and final gravity (just for fun and to verify), else I use my ref. throughout mash, boil, and fermentation to monitor every stage of the process. Now I can check gravity everyday of fermentation by just sanitizing the end of a probe thermometer and getting a drop out of the fermenter. Super fast and easy.

The Pol said:

You can find 20 vendors on Ebay with great feedback selling them for $30 or so shipped. Everyone I know, bought them there, and they are happy with thiers as well.

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Yep, I got an ATC Refractometer today ($29.95 shipped) thanks to this thread reminding me how convenient they are!! Thanks OP!

Neal

Boerderij_Kabouter said:

Now I can check gravity by just sanitizing the end of a probe thermometer and getting a drop out of the fermenter. Super fast and easy.

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This is the biggest reason I want one. Easy Peasy checking. And the immediate check of Preboil to make adjustment if needed.

useful thread:

https://www.homebrewtalk.com/f36/refractometer-vs-hydrometer-102547/