Ask The Brewmasters

  • 1.  Precise density measurement

    Posted 11-12-2021 12:14
    Hello,

    We are brewing low alcool beer using different technique.
    To obtain a below 0.5% Alc/vol beer we need to have very precise and accurate measurement of the density to make good choice over the procces.
    Right now we are using a easy dens and we find the tool practical for most beer and measurment.
    Perhaps, for low alcool beer where we aim slightly under 0.5% Alc/vol the easy dens seem to have to large of accuracy
    Easy Dens spec
    Accuracy     Extract 0.3 °Plato
    Repeatability (s.d.) Extract 0.2 °Plato
    Resolution Extract 0.1 °Plato

    We basicly start around 6.5 °Plato and end at 5.7 °Plato, sometime we do we do have to cold crash to end the fermentation.
    We pasteurize our beer once packaged.
    Analysis from the lab show different alcool then our calculation in the brewery wich we think is attributable to our reading.

    Do you know a really accurate tool to measure density or alcool that we could use in the brewery?

    We don't brew those beer to often so even a longer method of reading would be suitable.

    Thanks



    5 et 4

    ------------------------------
    Guillaume Boulanger
    Prod Manager
    La Barberie
    Quebec QC
    (418) 858-1346
    ------------------------------


  • 2.  RE: Precise density measurement

    Posted 11-12-2021 16:15
    Do you have a distillation apparatus and access to a precision scale?  You could distill the the sample and use a pycnometer to measure the density of distillate gravimetrically.  Using a chart you could figure out your ethanol concentration based on density.  The pycnometers can be a little bit tricky to use if you haven't used them before, but they do work and cost way less than the NIR alcolyzer units.

    ------------------------------
    Jason Weihbrecht
    Lab Manager
    Oskar Blues Brewery
    Brevard NC
    ------------------------------

    Original Message


  • 3.  RE: Precise density measurement

    Posted 11-12-2021 18:28
    Good point Jason.

    Pycs actually measure density by weight and volume.  The actual definition of specific gravity.  From the weight of distillate and beer one can accurately measure Alc, but the bonus is that one can determine Calc.Orig. Gravity, and Apparent Extract using the ASBC tables. Doing the test does require an extremely good Analytical Balance. Ensuring that the pycnometer is completely dry before weighing, and that the sample has been attemperated to precisely 20.0 C in a water bath is essential.  An Analytical Balance readable to 0.0001 gms is critical 

    My first job in the brewing industry, a long time ago, was in a regional lab for a very large commercial brewery. I must have done hundreds of Alcohol analysis using pycs. Later on the Anton Parr DMA  was used but the pycnometer is the method that is the check and balance for other methods.

    One caution.  Without the balance, and good distillation columns, and a perfect technique...the analysis is for naught. If you are to do pyc work ensure that the test is done in duplicates.

    Jim

    ------------------------------
    James Holden
    Brewing Consultant
    Retired but Busy
    jholden007@hotmail.com
    Canada/US/Mexico
    ------------------------------

    Original Message


  • 4.  RE: Precise density measurement

    Posted 11-15-2021 12:31

    I have never used the Anton Paar Easy Dens.  But I use the Anton Paar DMA-4500 and DMA-35 every day.  The Easy Dens appears to operate using the same technology, and I would expect greater precision and repeatability than what you reported.  I understand why you would not trust your Easy Dens, but maybe you can make it perform better.

    First, make sure the Easy Dens is clean.  You can use an enzyme detergent, or 0.5% NaOH solution.  Use distilled water to set the zero point.  Using an ordinary laboratory scale, you can easily prepare precise calibration standards with sugar and water to check your instrument accuracy in the range of interest.

    Next, pay close attention to your methods of sample preparation.  Suspended particulate and dissolved gasses could interfere with the measurement.  We filter our samples through a paper funnel with a few grams of diatomaceous earth into a screw-top jar.  Discard the first 25-50ml of sample to remove impurities from the filter.  If the sample filters slowly, cover the funnel to prevent evaporation of alcohol.  When the sample is filtered and the receiving jar is about half-way full, close the jar and warm it to room temperature (if necessary).  Then shake the jar several times and let out any CO2 pressure.  Let the foam settle, and then measure density.

    If you still cannot get your Easy Dens to work, I think the second-best instrument is the floating hydrometer.  When used carefully and correctly, the hydrometer gives highly repeatable results and the precision is probably good enough for what you are doing.  Hydrometers are not always accurate, but with sugar-water density standards and some patience, you can make a correction chart for your hydrometer so that it will be accurate.

     

    Cullen Dwyer

    Q/A Manager

    P: 978.874.9965 X1160


    Wachusett Brewing Company, Inc.
    175 State Road E.
    Westminster, MA  01473

    www.wachusettbrewingcompany.com

     




    Original Message


  • 5.  RE: Precise density measurement

    Posted 11-18-2021 16:55

    We have a scale but only get to 0.001gms, but one could be bought.

    I'm looking for Pycs as an option, we don't have a experience lab guy but are ready to learn.

    I'll be countinuing reading over the differenr option.

    Thanks for the precious answer!!



    ------------------------------
    Guillaume Boulanger
    Prod Manager
    La Barberie
    Quebec QC
    (418) 858-1346
    ------------------------------

    Original Message


  • 6.  RE: Precise density measurement

    Posted 11-15-2021 16:31
    Hey Guillaume,

    We have a Mettler Toledo Densitometer which reads densities down to the 0.01 (hundreths) of a degree Plato / 0.0001 (tens of thousands) degree Specific Gravity. I have found it incredibly helpful for my lab's contract low ABV% clients (NA beers, Kombucha, etc) who need accuracy to make sure their beverages are compliant <0.50%. We run ABV% analysis via Distillation (Method ASBC Beer-4B) and punch the precise Final densities of both sample and distillate into standard formulas in order to give ABV percentages down to 0.01% accuracy. I am not sure if Anton Paar's Densitometers go down to these low of degrees (but in the past using a DMA-35, I was not able to obtain 0.01 degree plato readings.)

    If you'd like to save time and money (vs running through a pycnometer/alcolizer) don't hesitate to contact me (my email and phone number are in the signature)! We would be happy to run ABV% testing for you.

    ------------------------------
    Daniel Neuner
    University of the Sciences - Brewing Sciences
    Malt Beverage Testing Lab Manager
    Philadelphia, PA
    609-670-5513
    https://sites.google.com/usciences.edu/maltbeveragetestinglab/
    ------------------------------

    Original Message


  • 7.  RE: Precise density measurement

    Posted 11-16-2021 10:58

    Hello Daniel 

    Thanks for the info. 

    Which densitometer from mettler Toledo are you using. 


    thanks



    ------------------------------
    Guillaume Boulanger
    Prod Manager
    La Barberie
    Quebec QC
    (418) 858-1346
    ------------------------------

    Original Message


  • 8.  RE: Precise density measurement

    Posted 11-18-2021 16:54

    Thank you for all the info,

    After reading your answer and lot of discussion we realise that our best bet might be trying to measure alcool in our beer for the cellar follow up.

    Does any of you have experience measuring below .5% alcool in beer. We are shipping to a labo right now.

    From my reading ebulliometer are not to accurate at his level perhaps one of our friend in another brewery find it pretty accurated when he compare it's result with gas chromatography result.

    I know that ENZYMATIC METHOD FOR LOW ALCOHOL CONCENTRATIONS with a spectrophotometer seem like an option but reageant seem fragile and could be a cause of false result.

    Thanks for the answer


     



    ------------------------------
    Guillaume Boulanger
    Prod Manager
    La Barberie
    Quebec QC
    (418) 858-1346
    ------------------------------

    Original Message


  • 9.  RE: Precise density measurement

    Posted 11-19-2021 12:42
    Howdy,

    The best way that I have found to measure low to no ABV beverages is using an HPLC. Granted those are generally cost prohibitive. Ebulliometers should not be used as they are not accurate. The cheapest, though not fastest or easiest way, is to use a lab distillation, as mentioned by others in the thread. There are a number of different methods (including ASBC-4). I recommend you research and decide which one is best suited to you.

    ------------------------------
    Reade Huddleston
    Head Distiller
    Butte MT
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    Original Message


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