Refractometer vs. Hydrometer

[WSURaider41]

I am just curious... what are the Pros and Cons for these two items? I am thinking of getting a refractometer, but before I do so I want to see if it will be worth my money. If it is worth my money, what kind should I get? Thinking about looking on eBay for one.

 

[SnallygasterBrewery]

Unless you buy one of quality, refractometers aren't necessarily any better than a cheap-o hydrometer. Personally, for ease of use/replacement cost should it break/relative accuracy I'd choose a hydrometer.

 

[ayoungrad]

Hydrometers are easy to break. Refractometers (at least so far) are harder to break.

I have both. I only got the refractometer for my last batch. I found it very useful. I was able to adjust my batch sparging and volumes to end up closer to my FG that I had in recent batches. And it only takes a few drops.

The main issues from my perspective for refractometers are the slightly inaccurate SG reading which is an apparently miscalculated conversion from BRIX. So I use BRIX instead. And also, you need to adjust BRIX (occasionally inaccurately) for the presence of alcohol once fermentation begins. Or use a hydrometer for FG.

 

[Bashiba]

I love my refractometer, great for checking batches throughout the boil and beats wasting a big sample at the end of boil or if your checking to see if fermentation has stopped. The only time I use my hydro is for the very last check at bottling or kegging, besides that sample is usually worth drinking by then.

 

[jkarp]

Refractometers are great for pre-fermentation gravity readings. Can't beat the convenience of pulling a sample straight from the MLT or kettle and not having to cool it first. You'll still need a hydrometer though for post-fermentation FG readings. Refractometers are pretty useless for that.

 

[Bobby_M]

It makes a lot of sense to have both. The more expensive refractometer is a time saver and convenience thing while the hydrometer is best suited for FG reading just before you rack or package. It also gives you the opportunity to sample a few ounces of product at the same time.

 

[clearshot798]

why cant you use a refractometer for fg

 

[WI_Wino]

why cant you use a refractometer for fg

The presence of alcohol skews the reading, it shows a higher SG than what it is. There are number of calculators on the web that you can use but it requires you to have an accurate starting specific gravity first. I believe that the calculators use formula(s) based on empirical measurement so it's an approximation.

Here are a couple of links:

http://www.northernbrewer.com/refractometer-calculator/
http://onebeer.net/refractometer.shtml

Personally I use a refractometer for starting SG and occasionally to check a SG midway to see about where it is. Final SG is always a hydrometer reading for me.

 

[smccarter]

With a refractometer you don't have to take a six ounce sample, wait for it to cool, then get your reading.... you simply take a spoon, scoop a small amount of wort from the mash tun or brew kettle, drop the very small sample onto the refractometer, close it, then get your gravity reading. You may have to set it down on the counter for a couple of minutes to allow it to cool for the best reading, but... still.. a very small sample that you don't have to cool.

Having said that... I used to take a six ounce sample from the brew kettle after sparging, wait for it to cool, take the reading with my hydrometer, then pour the sample back into the boiling brew kettle.

The comparison is this... with a refractometer, I take several readings directly from the mash tun throughout the process... I take a reading from the brew kettle right after sparging. Take several readings during the boil so that I can get as close to original gravity as possible. Take a reading while I'm cooling the wort if I want to, or after cooling the wort - and before moving it to the fermenter.

The hydrometer is used for taking readings from the fermenter, and after fermentation is complete to get my final gravity reading.

I like the hydrometer, but waste too much wort, or don't get all of the readings during the brewing process that I want.

 

[hilts]

Refractometers are great for pre-fermentation gravity readings. Can't beat the convenience of pulling a sample straight from the MLT or kettle and not having to cool it first. You'll still need a hydrometer though for post-fermentation FG readings. Refractometers are pretty useless for that.

Yep, I use both.

 

[Dan]

I'm glad you asked the question OP, because it made me think about this subject. Tried to lay my thoughts out. I don't think I'm far from off. There are plenty folks here know this subject better then me though.

Hydrometer Pros
- (calibrated) Accurate SG readings in wort or fermenting beer
- Works well with temperature correction adjustment

Hydrometer Cons
- Large sample volume. Waste wort/beer
- Doesn't work well measuring liquid not at ~68 degrees without temperature correction. The correction is not good after 159 degrees F.
- Easy to break.

Refractometer Pros
- (calibrated) Accurate SG readings in wort
- Tiny sample volume. Only need a few drops to test
- Auto temp correct (ATC)
- Doesn't break as easily as a hydrometer

Refractometer Cons
- Alcohol degrades the accuracy. When used to during fermentation, the reading needs a correction to give an accurate measurement. (Pro) -plenty of free online calculators available to compensate this anomaly.
- Even with ATC, a more accurate measurement will come after 30 second of cooling the couple drops on the glass lense.