Hydrometer calibration correction or replacement?

[dcbrown73]

My hydrometer came with my Master Vintner's six gallon winemaking kit.

I've been using it and my first reading on WE Barbossa Valley Shiraz was 1.078 which is less than expected. (the low end in the instructions was 1.080 to 1.100.) After speaking with AZMDTed, he said that was probably due to the sugars in my grape pack hadn't came out yet (probably should have measured the following day).

Once the seven days were over for first fermentation, I measured the final one at 0.994. After hearing it should be around 0.996 I decided to try and test my hydrometer using distilled water. It came out (if I remember correctly) at 0.996. This is at 72F, which I believe most are calibrated at 60F. Using a website that can adjust due to temperature, it says that from 60F to 72F basically only changes it about 1-1000th. (ie, a 0.996 reading at 60F corrects to 0.997 at 72F) So, clearly mine is off by at least three thousands.

While I haven't done the sugared calibration yet (28g of sugar in distilled water) I was wondering. Some people say don't buy a hydrometer that is under $10 because they are not good. My question is, if you actually calibrate your current hydrometer with distilled water and the 28g of sugar measurement (two point calibration) and adjust your scale reporting. Does it really matter if it's a cheap incorrect hydrometer as long as you have good correction data? Or is it something more fundamentally wrong with the hydrometer that I'm unaware of?

 

[AZMDTed]

You're thinking too hard

Calibrate the hydrometer in water close to the temperature it's rated for. Perfection isn't important because the correction for water temperature is fairly small as you saw. What's important is what the hydrometer says. If it says .996 that means that you're reading .004 low and for each reading you would add .004 to it. So in this case, your initial reading would be corrected to 1.082 (1.078+.004) and your reading in secondary would be corrected to .998 (.994+.004), well within where it should be going into secondary.

True accuracy is really only important for knowing when to go to secondary. For figuring out your ABV as long as you use the same hydrometer it will be consistently off and therefore give you an accurate delta, which is what you use to figure out the ABV.

I've never done a sugar test and don't think it's necessary.

 

[dcbrown73]

You're thinking too hard

Calibrate the hydrometer in water close to the temperature it's rated for. Perfection isn't important because the correction for water temperature is fairly small as you saw. What's important is what the hydrometer says. If it says .996 that means that you're reading .004 low and for each reading you would add .004 to it. So in this case, your initial reading would be corrected to 1.082 (1.078+.004) and your reading in secondary would be corrected to .998 (.994+.004), well within where it should be going into secondary.

True accuracy is really only important for knowing when to go to secondary. For figuring out your ABV as long as you use the same hydrometer it will be consistently off and therefore give you an accurate delta, which is what you use to figure out the ABV.

I've never done a sugar test and don't think it's necessary.

Thank you for the response.

btw, as for thinking too hard. It's a trait of mine. I'm an INTJ. I'm doomed to always be in this bottle!

 

[TonyR]

You can always pick up a good triple scale hydrometer and a test jar for $15. Always a very good idea to have a spare, they do break at the worst time. You are also trying way to hard. You are not in Chemistry class or working in a Pharmacy. Nothing in wine making is THAT critical. Have a glassof wine and relax.

 

[DoctorCAD]

Also, hydrometers are attracted to the floor, yours will go there some day.

 

[PhilDarby]

hydrometers are calibrated to only be accurate at one particular temperature any how, as ted said, you can fairly easily compensate for it.

As cad says no doubt you will drop it one day, at that time, you can decide whether to get a new better one.

Having said that and it might be some kind of record, I still have my original hydrometer I bought around 1985, although I have broken a few others in the meantime, or, upgrade it as the need dictates as I did and keep the one you have as a back up.

 

[richmke]

Consistency is more important than absolute accuracy.

The change in SG is what tells you ABV. Both readings will be off by the same amount and cancel.

When checking for the end of fermentation, you want to see that the SG doesn't change for a period of time.

If your fermentation stalls, then absolute level is important. If you know how much your hydrometer is off, then you can adjust for that.

 

[Dhaynes]

We always buy them in lots of 5. We find that having a lot of spares on hand tends to prevent breaking the one we are actively using

 

[pjd]

I'm probably going to loose the little bit of respect I have but I haven't used my hydrometer for at least a couple years. I normally make wine with Juice buckets and I finish them by taste. I'm not sure I even know where my hydrometer is. It was an important tool learning this craft but now... Maybe i'm just lazy.

 

[Arne]

I'm probably going to loose the little bit of respect I have but I haven't used my hydrometer for at least a couple years. I normally make wine with Juice buckets and I finish them by taste. I'm not sure I even know where my hydrometer is. It was an important tool learning this craft but now... Maybe i'm just lazy.

Gotta love home wine making. Lets you make it however you want to. No rules. As long as it comes out the way you want it, everybody is happy. . Arne