Refractometer and/or hydrometer

Hi folks! I have a hydrometer, and I used it religiously to test for completion (engineer here, on the anal retentive side of the brewing continuum).

That having been said, I also hate it. Too much volume, the thief is a pain, etc. is the refractometer correction (for alcohol) really that unreliable? I was thinking today that switching to a refractometer and pulling small volumes with pre-sterilized disposable pipettes would be awesome.

I just don't understand the refractometer drawbacks. Anyone want to fill in this information? Does the correction change more with larger OG-to-FG differences? I saw a site with some math, but that was just a curve fit against hydrometer data. Is there a non-empirical formula?

-b

the addition of alcohol throws off the refractometer to a level where it's completely inaccurate. it's good for pre-fermentation, but not for final gravity

refractometer for brewday.. don't have to cool off a bunch of wort to get a reading to see if you are in the proper range. Later.. use it for your OG/SG

Hydrometer for later. You can certainly wait for 10 days to take the first hydrometer reading. Four days later for another. and another 3-4 for your final gravity reading.. for normal beers.. High Grav brews will likely need more days for both the first one or two later readings.

I don't sweat it.. I leave my brew in the FV for about 15 days before my first hydrometer reading. Another 5 days for the 2nd. If I have questions, I'll take a third.. but, this is less than a 12 oz bottle of beer.. and I drink all of them. It's a good way to try to pick up on the slight differences in the brew as it progresses.

lumpher said:

the addition of alcohol throws off the refractometer to a level where it's completely inaccurate. it's good for pre-fermentation, but not for final gravity

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Although there is a good spreadsheet I've seen around to compensate for the alcohol content when using a refractometer for during and final refractometer readings. I know it's on the morebeer.com site.

Also, Morebeer sells a refractometer that has been calibrated to work with beer.. ie "wort" that has some level of alcohol in it. I have no idea how accurate it is... but, they say they put a lot of effort working with the mfg to design a meter that works.

The mentioned spreadsheet does compensate for the presence of alcohol to make the readings valid. I used it on the batch I kegged last and it matched the estimated FG on the brew. I plan on confirming another brew (the one in process now) to see how close it really is. I have a feeling that it's close enough to not matter for us.

Personally, if it's a SG point (or two) off it's not the end of the world. The batch won't be ruined or enjoyed any less because of it. The advantages of using the refractometer more than offset any potential negatives. Such as needing just a couple of ml to get a reading. Even that's more than you actually need. I typically use a 4 dram vial to reserve a sample for testing (OG and now FG). So that's 1/2oz in each vial reserved for readings. MUCH less than what you typically pull for a hydrometer sample.

I have two refractometers now. One from Bobby_M for beer and another that is a higher scale to test things like honey and maple syrup with (goes up to 80 brix). I look forward to testing some honey with the new refractometer to see what it's sugar content level really is.

HbgBill said:

Also, Morebeer sells a refractometer that has been calibrated to work with beer.. ie "wort" that has some level of alcohol in it. I have no idea how accurate it is... but, they say they put a lot of effort working with the mfg to design a meter that works.

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From their site...

Now Take Readings During or After Fermentation
In the past you could only use a refractometer during the brewing process, before the presence of alcohol. Once alcohol was present the reading was distorted and innacurate. Our free downloadable excel spreadsheet, and included how-to use video, now compensates for the presence of alcohol allowing you to use a refractometer from the start of the brewing process all the way to the finish of fermentation.

So, the refractometer has NOT been changed, they just tell you to use the spreadsheet...

A refractometer could, then, be used during fermentation to figure out if the gravity isn't changing...... Even if the gravity reading is inaccurate, it is still precise enough to detect fluctuations near the end of fermentation. Right?

I certainly don't mind using the hydrometer at bottling time because I already have fluid moving around... But I do lots of 1-gallon test batches, meads, etc., for which filling up my hydrometer sample jar is a fair loss of volume. I don't worry about fermentation, but I am a data-driven guy, so I like to test.

Just use the spreadsheet, or other software, to 'translate' the refractometer readings (once alcohol is present) to true readings.

Personally, I don't take any readings once I pitch the yeast. For beers at least. In my initial mead batches I was taking readings until I hit the 1/3 break. This time around I just left them along, making sure I gave enough nutrient at the start for the yeast (it's another method, fully valid).
Still, for a beer, I'll take the OG, then a FG reading (so that I know what I ended up with). Less times going into the batch means less chance of something going sideways on me.

My refractometer and hydrometer differ by about .002 at FG so I just go by the refractometer....if the value makes sense all I care about is that it's not changing any more...I will take a hydrometer on occasion during the cold crash period to satisfy curiousity, but not often.

Gulp.. you are correct.. I had a brain fert.. it's Brix and SG. no conversion there.

helibrewer said:

My refractometer and hydrometer differ by about .002 at FG so I just go by the refractometer....if the value makes sense all I care about is that it's not changing any more...I will take a hydrometer on occasion during the cold crash period to satisfy curiousity, but not often.

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This.

HbgBill said:

Gulp.. you are correct.. I had a brain fert.. it's Brix and SG. no conversion there.

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Thought I smelled something... It has ATC (temperature correction) which is great when you're in the brewing process and want to check the results. Not that I have since I care more about what OG I get once I'm about to pitch the yeast. If I miss my OG, I just roll with it. Sometimes I'm above what I expected, sometimes below... Either way, I know I'll have great beer. :rockin:

Since the introduction of the correction spreadsheet, I see no need for a hydrometer. WAY too much beer is needed. For me...doing 1 gallon, no way.

I downloaded the spreadsheet and it is all zero's. ????

I think I will switch to a refractometer and see how it goes. I was hoping for a shortcut chart-on-the-wall kinda thing for the correction, but if I have to use the spreadsheet it is no trouble. Most of the time I am just looking for relative change during fermentation.

I don't normally do 1-gallon beer batches, but I have been considering it for test recipes and splitting 1 wort batch multiple ways for different dry hopping or fruit additions (hence this entire discussion).

I ordered the refractometer with ATC from Amazon recently.. hoping it would arrive in time for the Big Brew day sponsored by AHA. Well, Aha.. it didn't arrive until the Monday after the event.. dern. But, I think I'm going to like it. Who knows if I'll get around to trying to use it during/after ferment. But, what the heck, it's just another part of brewing that could add to the fun/interest in the process.

Hey.. "Mikey likes it"

I use both, but rely on the hydrometer reading for pure accuracy. I use multiple nice lab hydrometers that have smaller scales on each (it makes it easier to get a more accurate SG reading). Even with conversion sheets, I find the refractometer off (not by much), but I'd rather have the accuracy of the hydrometer. The SG's on brew day of sparge runnings, pre-boil, etc I do with the refract. OG, I always do with the hydrometer, and especially FG (which is where I find it to be off more)

I like having both. I use the refractometer much more, because it is more convenient and you only need a tiny sample.

Beersmith has a built-in calculator that will correct the refractometer reading for final gravity.

The other really useful thing is you can use both a hydrometer and refractometer simultaneously to get a good approximation of ABV even without an OG reading (for example you forgot to take an OG reading or it was inaccurate for some reason). This has been a lifesaver for me.

I use a refractometer for prefermentation readings- preboil gravity and the OG into the fermenter. I use a hydrometer at the very end before bottling/kegging.

Beersmith has a refractometer tool that works pretty well, because a refractometer has to be "calibrated" with an adjustment to compare it to SG. My brix correction factor is .01544. I think that's a common adjustment, in that area. Then you can compare the SG with the refractometer reading of unfermented wort.

Once alcohol is in the mix, I haven't had any accuracy at all with getting a good FG reading with a refractometer.

I also use the refractometer for checking the sugar content (in brix) of fruits for wine making. It's especially great for that.

From what I have seen almost all refractometer tools, Beersmith included, use a totally crap formula for the calculation making the readings inaccurate. If you want to use a refractometer I suggest you check out the research Sean Terrill did and use his improved formula http://seanterrill.com/2011/04/07/refractometer-fg-results/

I use the Brewzor Calculators app for android. It has a refractometer correction calculator built in that works great. I have verified the readings against a hydrometer on multiple batches and am fully confident in the readings. I NEVER use a hydrometer anymore. The app by the way is free