Accuracy of the $6 hydrometer vs $30 precision hydrometer

[NorCal]

Since I have and use both: the Amazon lowest cost hydrometer and a precision one, I thought it would be of interest to provide a comparison, at a time when you need it the most. Readings were made at the same time and location of a macrobin of 1,000 pounds of Cab Franc.

I would read the $6 as 1.5 brix, the $30 clearly greater at 2.5 brix. Significantly different. In most cases, this level of accuracy is not a big deal on a low volume hobby basis. When you put out a thousand or more $ for a thousand pounds of grapes, it’s worth the additional $24 to know with accuracy where your ferment is. The difference in the measurements made the difference of pressing one or two days later.

 

[Rice_Guy]

and, ,,, of course we could also cause a one brix shift via juice temperature

 

[distancerunner]

Buck or so a pound?

I wish!

Good work can be done with crappy tools but it takes a lot of skill and experience. Good tools make the job easier and more accurate.

The price of a good tool is quite often the price of a cheap tool plus the tool you should have purchased in the first place.

 

[heatherd]

Since I have and use both: the Amazon lowest cost hydrometer and a precision one, I thought it would be of interest to provide a comparison, at a time when you need it the most. Readings were made at the same time and location of a macrobin of 1,000 pounds of Cab Franc.

I would read the $6 as 1.5 brix, the $30 clearly greater at 2.5 brix. Significantly different. In most cases, this level of accuracy is not a big deal on a low volume hobby basis. When you put out a thousand or more $ for a thousand pounds of grapes, it’s worth the additional $24 to know with accuracy where your ferment is. The difference in the measurements made the difference of pressing one or two days later.


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I am surprised there is that much difference! Where did you get the precision one?

 

[crushday]

@NorCal - thanks for posting this little experiment. I wonder what the reading of the "cheap" hydrometer would be if placed in the same reservoir as the 55. Likely no difference but the test would have one less variable.

 

[VinesnBines]

I have three cheap hydrometers. Two register the same and one is one brix off (lower). I remember to use the same hydrometer for a batch.

I plan to get a more precise hydrometer, eventually.

 

[NorCal]

The reason this came about was that for logistics reasons @Busabill is fermenting his grapes at my barn. I‘ve been giving him brix updates along the way with the $6 and we were getting near the end. He came over to press before he left for the 3 day weekend because it should have been below 1 brix. I broke out the precision one and it read 2.5 and we didn’t press, but rather did some barrel tasting

After he left is when I did the side by side measurements and found the reason I provided bad information to him.

The +5 to -5 hydrometer is available on Amazon.

 

[VinesnBines]

I discovered my differences with a stuck ferment. I was using all three in three buckets. I was switching the hydrometers around and puzzled by the changes (up and down) of the SG.

 

[ibglowin]

Even the cheap hydrometer can be "calibrated" by sticking it into distilled water and noting the temp for additional temp adjustment. Just make a note if it reads something other than 1.000 and add/subtract that value from any must measurement in the future.

 

[Jim Welch]

Even the cheap hydrometer can be "calibrated" by sticking it into distilled water and noting the temp for additional temp adjustment. Just make a note if it reads something other than 1.000 and add/subtract that value from any must measurement in the future.

First thing I do when I get a new hydrometer is calibrate in distilled water. I broke my bottling hydrometer a couple weeks ago and just received 2 replacements Wednesday. Within 5 minutes of unboxing I had them calibrated with temperature correction.

 

[mainshipfred]

Interesting, I have 3 triple scales that all read the same so I assume they are accurate. I also have 1 finish hydrometer. I'm not as concerned about the initial reading and always check it against the refractometer. I start using the finish when I get below 1.020. It's really nice getting a more accurate reading. If someone is trying to get a finish hydrometer be careful, they'll just break by looking at them the wrong way.

 

[Earldw]

First thing I do when I get a new hydrometer is calibrate in distilled water. I broke my bottling hydrometer a couple weeks ago and just received 2 replacements Wednesday. Within 5 minutes of unboxing I had them calibrated with temperature correction.

Yeah, I’ve had bad hydrometers and a one point check with water will tell you if the little piece of paper on the inside is in the right place. If you have a bottle of grain alcohol around you can do a two-point check and find out if the little piece of paper is calibrated to the bulb. I know Norcal is giving us the abbreviated results, but without testing against a know standard we don’t know which hydrometer was accurate, right?

 

[Jim Welch]

Yeah, I’ve had bad hydrometers and a one point check with water will tell you if the little piece of paper on the inside is in the right place. If you have a bottle of grain alcohol around you can do a two-point check and find out if the little piece of paper is calibrated to the bulb. I know Norcal is giving us the abbreviated results, but without testing against a know standard we don’t know which hydrometer was accurate, right?

That’s interesting, I’m going to do that out of curiosity. I have 99.9% Isopropyl alcohol and a bottle of 95% grain alcohol. I’ll be searching for their SGs when I get on my computer.
I’ve previously considered making a known concentration of sugar water by carefully weighing the sugar and water to do this on the upper range of gravity. But am not sure if say one takes 250 grams of cane sugar dissolved in 750 grams of distilled water would make a precise 25 Brix solution. Intuitively it seems it would but I’m not 100% sure if is that simple.
Not that I think this is THAT important but my German ancestors have handed down a proclivity to go way beyond what’s need to “get by” in most things I do!

 

[Raptor99]

One degree Brix is defined as 1 gram of sucrose in 100 grams of solution. So you could easily make a 25 Brix solution.

 

[NorCal]

@crushday had a good point, so this morning I took away the variable of the container. Same results.

 

[Cap Puncher]

It is definitely important to calibrate the +5/-5 precision finishing as well. I thought I got a a good deal on a precision 0.980 - 1.020 hydrometer for $10 at northern brewer. Mine is 0.975 with distilled water at 60F. I use a 0.025 correction on all my readings. It’s pretty annoying to have to correct on the “precision” item (I should stop being so cheap and get a more expensive one).

 

[balatonwine]

Are both hydrometers standardized at the same temperature?

I ask, as looking at Amazon (you did not give brand names so I simply looked at hydrometers within each price range), the cheaper one I found was standardized ?? (it did not say) and the expensive one was standardized at 20°C.

If (big if) the standardization for yours differed (some are standardized to 15°C), then side by side comparisons are not valid. You gotta do the math to really compare them if their standards differ.

In any case, you really need to also take the temp of your must to correct even the "precision" expensive one, as it will give an inaccurate reading if the must is not at it's calibration temperature.

Hope this helps.

Edit: Seriously... Always buy the best you can afford. You will not regret it.