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It is important for any brewer who wishes to get the most consistent results possible to keep his or her brew house calibrated. Knowing your measurements and calculations are accurate will allow you to better predict the way your final product will turn out.
So what are some things you should look at when calibrating your equipment? In this article I will go over what it is you can do to make sure your equipment gives you the accurate results you need.
Your hydrometer is important to know the amount of alcohol you will end up with, as well as figuring efficiency, and knowing if fermentation is complete, with all these tasks it is imperative to know you are getting an accurate reading.
To test your Hydrometer first you must know the temperature your particular hydrometer is calibrated to, this information should be printed on the instructions for your hydrometer, or on the hydrometer itself. The solution to be tested must be at the specified temperature to get an accurate reading however there are calculators both online and built into some brewing software that allow for you to correct your reading if the temperature is not in the correct range.
Hydrometers are made to read 1.000 SG in distilled water at the correct calibration temperature for the hydrometer. To calibrate your hydrometer fill the sample tube with distilled water at the correct temperature place the hydrometer in the water, and spin it to release any air bubbles that may be trapped below it. Check the reading on the hydrometer, if it is 1.000 it is working fine if it is off, you can add or subtract the amount it is off to get an accurate reading.
Eg: If your reading is 1.004 you will need to subtract .004 from your reading next time to have an accurate reading.
Refractometers are also temperature calibrated, however many of them feature ATC, (Automatic Temperature Correction) and will make the temperature correction for you. Refractometers can be off as well and should be calibrated according to the manufacturers directions, usually with distilled water.
Refractometers are inaccurate in the presence of alcohol and a alcohol correction calculator must be used, or preferably a hydrometer to determine the FG, it is a common mistake made by new brewers, when they think their fermentation is stuck, but really the alcohol is throwing off their refractometer.
Every brewer should have a thermometer it is one of the simplest, yet most vital parts of any brewers toolbox. If inaccurately calibrated a thermometer can cause great headaches, especially for the all grain brewer. Inaccurate thermometers lead to off mash temperatures, which leads, to unknown fermentability of your wort.
To check the accuracy of your thermometer you will need to check the temperature of two solutions with a known temperature. To do this you will want to preferably use distilled water.
Freeze an ice tray with the distilled water fill a glass tightly packed with the ice and more distilled water, set this glass aside and allow the temperature to even out. (probably about 5-10 min)
While your ice water sits fill a small saucepan with distilled water and bring it to a boil. (NOTE: you will need to know the boiling point of water at your local elevation for this to work.)
Now test the temperature of the two solutions, make sure to move the thermometer around and allow it appropriate time to give a reading, some of the cheaper thermometers can take a few seconds to give a solid reading.
The temperature of your ice water should be 32F or 0C.

The boiling point at sea level should be 212 degrees F or 100 degrees C.

Assuming your readings are accurate, you can now use your thermometer with confidence!
If readings are off most of the nicer thermometers, and some of the cheap ones will allow you to adjust the calibration, refer to the instructions that came with the thermometer to adjust if needed, likely you will need your ice water & boiling water so don't toss them if you need to re-calibrate.
Personally I use a very cheap thermometer which I find very accurate, and when the accuracy gets off I replace it, however it is possible to make a correction chart or possibly do simple math if the thermometer is +/- the same amount on both of your readings.
Scales can become off quite easily making it possible to add too much or too little of whatever it is you are weighing, throwing off your beer. Scales should be checked for accuracy often, using something of a known weight. Most scales can be calibrated by using a weight of a certain size according to the directions of your particular scale. Weights of the appropriate size can usually be found where you bought your scales, or online.

Brew Kettle

It is important to know a couple of things about your brew kettle during the brew, volume & boil off rate. Both of these things can be checked at the same time start by taking a pitcher with volume marks and slowly fill the kettle, as you fill the kettle take either your spoon, or paddle, or something else you can mark with volume levels (I use the back of a yard stick) and mark each half or full gallon as you fill the kettle.

Now, with a known amount of water in the kettle bring it to a boil for one hour. After an hour remove it from the heat allow it to cool and check the volume again the amount of water missing is your boil off rate.
Once you have figured out your boil off rate, you can take measurements of your kettle and put all of this information into the brewing software you are using to customize it to your equipment, this will help later when developing recipes.
If you are an all grain brewer you will also want to figure out your normal efficiency percentage so you can use it when inputting new recipes to better predict your OG, here is a online calculator which can help with that. http://www.brewersfriend.com/brewhouse-efficiency/
Knowing that your brew house is calibrated is important for achieving repeatable results and making accurate predictions, and should be done at least once per brewing season to ensure accuracy. Now that you have calibrated your brew house you are ready to make great, repeatable, and predictable beers time after time!
When calibrating the thermometer, keep the probe from touching the sides of the glass or pan when taking a reading.
@Ski12568 Good point the pics don't clearly show that & I probably should have mentioned it. It is best to get your reading from the middle of the liquid.
It's a lot harder to hold a thermometer in one hand over a steaming pot & take a clear pic in the other with out burning yourself lol
Water is not a solution, it's a liquid.
It is important to stir the ice bath. The maximum density of water is at 4C. It is bad practice to stir with the thermometer, but people do it all the time.
@Wynne-R, I think you mean water is a substance, not a solution. It is a pure solvent. Liquid water is a state.
Thanks for the reminder that I need to check my cheapo thermometer. Been a while.
Mash temps are my albatross. But after 7 batches in, at least I know where improvement is necessary. Where I live, 208F seems to be the accurate boiling temp. Cheers.
One way to calibrate a scale, if you don't have weights, is to use nickels. They are 5grams each. Use clean ones and use multiples in order to up the weight...10 nickels is 50 grams and so forth.
I just wanted to add some of my own experiences, as I'm sure this didn't happen to just me.
If the hydrometer is off by x-points in calibration water. It doesn't mean that it will be off by an equal amount of points at lets say 1.060 SG. You should always doublecheck a new hydrometer with water, and making a known solution of wort, or sugarwater or whatever. The scale inside the hydrometer might be off.
This goes for refractometers too. I've had an e-bay refractometer where the brix-scale was off comparing to the SG scale. This can lead to some serious errors if you use it to convert from Brix after fermentation has started.
Thanks Kyle! I appreciate the write up. This will definitely help with dialing in my equipment. I appreciate the efficiency calculator at the end as well. Cheers
Refractometers: I need one and Northern Brewer has them for $60 with a range of 0-32 brix and corresponding SG scale and automatic temperature adjustment. Amazon has what appears to be the exact one name brand and all for $24 as well as a price range of $21-$150 for the same range and features they all look pretty much alike. And EBay has them starting at $15! Is there a difference that I'm not seeing or that's not being listed in the descriptions?
If so can anyone recommend a good one and a website to get it at?