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Weight Instead Of Volume For Proofing

Hello again you lovely people,

we use volume calcs currently for proofing down, do you guys use volume for this and if so have you any good conversion tables to help me with it?

thanks again



  • Weight/mass is much better than trying to use volume.

    Alcodens is great for professional use, but requires a Windows computer and costs around $300 if I remember correctly. If you have a mobile device, search for "Whiskey Systems Calculator". It's free.

  • that's much appreciated thanks gents. do you leave your spirit on the scales and then proof down?

  • if i use a volume proofing calculator that gives me the required volume of water required to the percentage of proofed spirits, can anyone help explain to me how this will change in regards to temp? for example its 10deg Celsius in our workshop right now compared to the 20 in the summer,

  • with proofing calcs by volume its working on 100% ethanol, 1 liter of alcohol = 0.789 kg (for density of alcohol = 789 kg/m3) if my product comes off the still at 75% abv is it normal then to make up the 25% with water by weight? last thing also sorry gents, does temp effect weight also?

  • edited January 2022

    The reason so many of us professional distillers use weight (mass) is that it's incredibly easy compared to trying to use volume, which tends to have significantly more error. Why? Because you need to take into account the temperature of both liquids being blended, as well as account for the temperature rise of the blend. Having to get every potential blending tank calibrated and a custom level stick made is a real pain in the ass. In addition, large diameter tanks can have far more error. Error means you are going to be doing a ton of trial-and-error proofing, wasting a ton of time.

    Scales are easy once you get a tool to help automate the calculations (like alcodens). Alcodens is 200 bucks, for a commercial distiller it's worth every penny. The LQ that allows for sugar blending is $300.

    Never used Whiskey Systems calculator. I trust alcodens because he knows what he's doing, and knows his math. I've validated the calculations in alcodens on paper to confirm accuracy.

  • edited January 2022

    thanks again @grim, will definitely invest in the alcodens software then, can i ask about LQ?

  • googled it and found it thanks, alcodens LQ :)

  • Alchodens does take a little bit of getting used to. Another free mobile app that I've found very handy is Hoochware.

    It has a heap of useful calculators for guaging, blending etc using both weight and volume that take temperature into consideration

  • edited January 2022

    Thanks @crozdog, that's much appreciated. will get hoochware downloaded the now.

  • edited January 2022

    In another forum, one gent posted this Excel worksheet. Very useful to use where everything is automatically worked out with VLOOKUP tables. In this example I have blended three batches together with water for a 30% ABV mix ..... Green and salmon shaded are for input.


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  • edited January 2022

    NEVER proof by volume.

    Always by mass.

    For example, 40% ABV = 33.30% ABW (alcohol by weight), at 20 degrees C.

    Mass will be the same, no matter what the temperature of the liquid is. Volume changes with temperature.

    Besides, how do you accurately measure volume?

    Largest graduated cylinder we have is a mere 2 litres.

  • edited January 2022

    Thanks @Homebrew, would it not be 40% by volume? Trying to get my head around it thanks.

    And thank you @richard, could i get a copy of that spreadsheet off you if possible?

  • edited January 2022

    @Homebrew do you have any good links for floor scales?

  • Yes, the example I gave you - 40.00% by volume (ABV) is 33.30% by weight (ABW), at 20 degrees C.

    If your liquid is cold, hot, or lukewarm, if you proof it by mass (example 33.30% by weight above), then it will be 40.00% by volume (for example), no matter the temperature of your liquid when diluting.

    Hence you should always proof (dilute) by mass, not volume.

    I work to 2 decimal places.

    In Europe, we are required to bottle our spirits with the ABV normalised to 20 degrees C. i.e. the ABV on the bottle is only applicable when the liquid is 20 degrees C.

    As for floor scales, I use Adam.

    They are very stable after calibrating, and do not "drift" like other cheaper scales I have bought.

    If you are producing commercially, the accuracy of your scales is really important.

  • edited January 2022

    Thanks again @Homebrew, will have a look at the adam scales. 40.00% by volume (ABV) is 33.30% by weight (ABW). Do you have any charts or calcs you use for proofing?

  • ABW = ABV * 0.79336 is this the formula?

  • edited January 2022

    @laconnings said: ABW = ABV * 0.79336 is this the formula?

    Absolutely not!

    There is no formula - do not try to use one. The relationship of ABV to ABW is not linear.

    I use AlcoDens - it implements the Practical Alcohol Tables.

  • edited January 2022

    Thank you @Homebrew, Alcodens has been mentioned previously so I will get that sorted once I’m back on dry land.


  • edited January 2022

    I’m getting this when I enter 40%abv for 1 liter at 20 deg c, where am I going wrong?


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  • @laconnings said: thanks Homebrew, would it not be 40% by volume? trying to get my head around it thanks. and thank you Richard, could i get a copy of that spreadsheet off you if possible?

    Unfortunately it's not mine for distribution

  • @laconnings said: ABW = ABV * 0.79336 is this the formula?

    As mentioned above, NO. This is an example as to how Density changes with ABV


    abv table.png
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  • edited January 2022

    That’s much appreciated, cheers @richard

  • @laconnings

    Are you planning to produce commercially?

    How are you currently taking the ABV of your distillate?

  • Still using free "Liquor Proofer" android app and loving it.

  • What kind of volume are you guys proofing at a time? 20 gallons? 55? More?

    And How precise does a floor scale need to be to give you accurate results? Dan

  • edited January 2022

    @Homebrew I am planning on producing commercially but haven’t started yet with it, currently running off hydrometer and volume for our test runs

  • edited January 2022

    Will check it out thanks @CothermanDistilling

  • But then to further muddy my waters, going on weight for proofing, if adding syups, sugars or honey to the spirit they clearly weight more, honey for example is 1.4kg per liter, if I followed weight for that then the proof would be way off? Currently I add honey and water into a measuring tank and mix until I have the correct amount of honey water to proof down the spirit.

  • Correct, adding sugar or anything else will change the density. And you won't be able to take an ABV reading directly.

    Calculating ABV/ABW from density is only possibly with water/ethanol mixtures.

    Make sure you are using a decent hydrometer, like the ones Stevenson Reeves sell.

    Also a thermometer that has been calibrated.

    Not the cheap stuff from the home brewing shops.

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