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DMS Reduction in lagering beer

  • 1.  DMS Reduction in lagering beer

    Posted 08-14-2019 12:55
    Hello all,
    We are narrowing down the cause of excess DMS in some of our beer and in the mean time are looking for ways of reducing it in finished product.

    Does anyone have any tricks to reduce DMS in pale lager?

    ------------------------------
    Jonathan Porter
    Owner / Brewer
    Smog City Brewing Co
    Torrance CA
    (310) 320-7664
    ------------------------------


  • 2.  RE: DMS Reduction in lagering beer

    Posted 08-22-2019 19:21
    Hello Jonathan,

    ​Dimethylsuiphide(DMS) is an organic sulfide with 2-methyl groups. It has a fairly low boiling point of 38 deg C and a flavor threshold of above 30 ppb. Most lager beers contain DMS at or near the flavor threshold, and its impact at these levels is beneficial to beer flavor quality.When beers contain 2-3 times the threshold, they have a characteristics sweet corn, cooked corn, tomatoes and black olive flavor which is undesirable.
    DMS found in beer originates as S-methyl methionine (SMM). SMM is broken down to DMS, some of which is volatized and removed while some DMS is oxidized to Dimethyl sulfoxide (DMSO). DMS levels in beer are overwhelmingly related to raw materials, brew house issues and fermentation conditions. Measures taken to reduce the levels of DMS will target these 3 areas of the process.

    1. Raw material- Check your malt specs and ensure low SMM malt specifications. However, watch out for high colors arising from over- kilning of the malt. Most Maltsters know the favorable malting conditions to ensure low SMM and thus low DMS.
    2. Brew house- Wort boiling processes will affect the levels of DMS formed in wort. Such practices that affect the levels of DMS in brew house include
    a. Aim to get high evaporation rates of between 7-10%, avoid kettle condensate return to wort, ensure vigorous, evaporative,longer boil and avoid late hopping.
    b. Extended hot wort tank times and whirlpool delays will increase DMS.
    c. Prolonged wort cooling times ,too long whirlpool rest stand times will increase DMS.
    3. Fermentation - Conditions that will increase DMS include under pitching, poor yeast vitality and viability, sluggish fermentation, Certain types of yeast strains and low fermentation temperatures.
    4. Hygiene - Infections due to poor hygiene and beer spoilage bacteria such as Hafnia, Thermic bacteria, O. proteus and Enterobacter species  will reduce DMSO to DMS, increasing the DMS in beer.
    5. Carbon dioxide - CO2 produced during fermentation strips beer of DMS and if not well purified and it is reused in blending or carbonation process, can increase DMS in packaged beer.
     
    I hope this helps as you check through your process to see areas of improvement. Share with us how it goes!

    Best of luck

    ------------------------------
    Chika Ezeani
    Brew Master
    Kerry, (Taste & Nutrition Company)
    Beloit WI
    (608) 201-9707
    ------------------------------

    Original Message


  • 3.  RE: DMS Reduction in lagering beer

    Posted 03-21-2023 17:27

    Hello all, we are on our own DMS journey and as I looked back through AtBM threads I came across this post. Above Chika provides an excellent outline on DMS control but I was specifically curious to this statement regarding brewhouse management "...avoid late hopping."

    Can anyone speak to the correlation between late hopping (I assume end of boil and whirlpool additions) and perceivable DMS in beer? Is this a function of changing boil kinetics, hot wort clarity, hop chemistry, or other? Has anyone changed hopping additions, rates, or products in response to a DMS problem? I am developing a list of process variables to work through on our brewhouse and have the usual suspects on the list, but this was one I certainly hadn't thought about. 



    ------------------------------
    Campbell Morrissy
    Head Brewer
    pFriem Family Brewers

    PhD Candidate
    OSU - Barley Project
    ------------------------------

    Original Message


  • 4.  RE: DMS Reduction in lagering beer

    Posted 03-22-2023 13:01
    Hi Campbell,

    There is a good 2019 TQ article that discusses thiols in dry hopping that can cause DMS:


    I found the following statement from the above article particularly interesting:

     "Owing to the extremely low odor-detection thresholds of thiols (ng/L) (14,71,72), minor changes in thiol concentrations can have a large impact on beer aroma. However, due to the very low concentrations of thiols in beer (ng/L) and in hops (ng/g), the complexity in measuring sulfur-containing compounds has limited much of the work performed on these analytes until relatively recently. Some sulfur-containing compounds (such as  dimethyldisulfide, S-methylthio-isovalerate, and S-methylthiohexanoate) (71) have been related to unpleasant aromas in hops such as "onion" or "garlic." Nevertheless, the influential positive role of polyfunctional thiols (mainly 4-mercapto-4-methylpentan-2-one, 3-mercaptohexylacetate, and 3-mercaptohexanol) in hop and beer aroma has been highlighted in several papers (73–78). One must keep in mind that thiols can exist in hops as both thiol precursors (odorless) and as free thiols (potent odors) (32,77).

    Hope this helps.

    Dana

    --

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    Technical Director, Craft Brewing | Birko - A Diversey Company

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  • 5.  RE: DMS Reduction in lagering beer

    Posted 03-22-2023 17:18

    Hello, Campbell. See the references here: https://www.milkthefunk.com/wiki/Dimethyl_Sulfide#Production_From_Hops

    The small amount if DMS/DMSO in hops may not be anything to worry about, especially considering the high late hopping rate of other styles.



    ------------------------------
    Dan Pixley
    Milk The Funk Wiki Editor
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    Original Message


  • 6.  RE: DMS Reduction in lagering beer

    Posted 04-03-2023 15:10

    Great information in this thread.
    I have heard this comment in chika's writeup over the years. .
    Aim to get high evaporation rates of between 7-10%    , 

    are we talking about 7-10% total? or 7 -10% per hour? 




    ------------------------------
    Michael Smith
    Head Brewer
    Eel River Brewing Co.
    Fortuna, CA
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    Original Message


  • 7.  RE: DMS Reduction in lagering beer

    Posted 04-04-2023 14:35

    Hello Michael,

    The aim is to get high evaporation rates of between 7-10% total at the end of wort boiling in most conventional wort kettles. 

    Some modern wort kettles have improved evaporation efficiencies for unwanted flavor components by increasing the surface contact between the heater and wort, and thus evaporation rates of 5.50% -6.0% is achieved in less than 60 minutes boil time.

    Hope this helps. 



    ------------------------------
    Chika Ezeani
    Brew Master
    Kerry, Taste and Nutrition
    Beloit WI
    (608) 201-9707
    ------------------------------

    Original Message


  • 8.  RE: DMS Reduction in lagering beer

    Posted 04-04-2023 18:59
      |   view attached
    G'Day Chika
    I think more intense/longer boils are a two edged sword.  Yes, you will remove more of the undesirable volatiles like DMS.  However, you will also impact the foam stabilising potential of your beer.

    Van Nierop, S. N. E., Evans, D.E., Axcell, B.C., Cantrell, I.C., and Rautenbach, M. 2004. The impact of different wort boiling temperatures on the beer foam stabilizing properties of lipid transfer protein 1. Journal of Agricultural and Food Chemistry, 52, 3120-3129.


    There are of course ways to 'have your cake and eat it' by judicious selection of boiling parameters.

    Robinson, L. H., And David P. Improving foam quality through wort boiling optimisation.  Proceedings of the 30th Convention, The Institute of Brewing and Distilling, Asia Pacific Section, 2008 Auckland, New Zealand, 6-11 April. paper #12. (see attached).

    Cheers
    Evan
    --
    D. Evan Evans
    The Tassie Beer Dr, FIBD
    Lindisfarne, Tasmania, Australia
    ph 0402-204-319 / +61-(0)3-6243-9556






    Attachment(s)

    pdf
    Robinson and David IBD-2008 foam.pdf   70 KB 1 version
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  • 9.  RE: DMS Reduction in lagering beer

    Posted 03-22-2023 13:01

    Chika has provided some great information, but I can share some things I've learned over the years.  I would check to make sure that steam from the kettle is being evacuated properly and condensate is not able to run back into the kettle.  SMM, the precursor to DMS, will convert into DMS when heated and quickly flashes off when the kettle is at a rolling boil.  As mentioned I've seen increased levels of DMS if beer gets held up in the whirlpool because it stays hot, but not boiling for a longer amount of time.  During that time SMM is converting into DMS and not flashing off since you are no longer in a boil.

    As a rule of thumb we would see the concentration reduce by half from wort to beer.  For example if we measured 300 ppb in wort it would be roughly 150 ppb in finished beer.  

    My immediate recommendations would be to check your steam evac, check for condensate (if your steam evac pipe is too long you will need to have a way to divert the condensate from running back into the kettle because it contains DMS), and check your evaporation rates.  Next I would make sure you finish in the kettle with a rolling boil and then try to get your worth through the whirlpool and to the heat ex as quickly as possible.

    Best of luck!



    ------------------------------
    Jason Weihbrecht
    GM of Brewery Operations
    Oskar Blues Brewery
    Brevard NC
    ------------------------------

    Original Message


  • 10.  RE: DMS Reduction in lagering beer

    Posted 03-23-2023 11:35

    I was talking to a couple of brewers from Mexico last week about this at Copa Pacifico, and one of them declared that they fix it by recirculating the Brite tank thru a length of copper tubing. I know this is supposedly effective against Sulfites, but am not sure about sulfides. Easy to implement and might be worth a try.



    ------------------------------
    John Palmer
    Owner
    Palmer Brewing Solutions Inc
    La Crescenta CA
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    Original Message


  • 11.  RE: DMS Reduction in lagering beer

    Posted 03-24-2023 11:50
    Mr Palmer,
    I've heard you say that copper exposure after pitching catalyzes staling.  Has that been disproven?

    Prost



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  • 12.  RE: DMS Reduction in lagering beer

    Posted 03-27-2023 13:26
    Regarding Copper catalyzing staling:
    Yes, that is true and has been described in the literature, but with regard to the reduction of sulfites and thiols, there is (or would be) the question of which is the bigger problem in a given situation. Fortunately, Eric was able to correct me with regard to DMS, so we won't have beers suffering from both DMS and Staling due to copper pipe recirculation. DMS is a chemical reduction of DMSO, so exposing DMS to copper, a reducing agent, wouldn't do anything.  But it would be nice if there was a way to oxidize it back to the DMSO or SO2 and thence to a more benign SO4-.


    I should have re-read this before posting previously.
    Cheers,
    John



    Original Message


  • 13.  RE: DMS Reduction in lagering beer

    Posted 04-02-2023 14:05

    See 

    Control of sulphury impurities in beer aroma
    First published: March‐April 1971
    https://doi.org/10.1002/j.2050-0416.1971.tb03367.x


    In their abstact they note:


    It has been found that not only may traces of copper be dosed electrolytically into beer with great precision but that the copper so dosed reacts nearly quantitatively with the volatile sulphur present, thus abolishing the latter with no appreciable increase in the net copper content of the beer. The process has given satisfactory results on an industrial scale, improving the flavour of beers without prejudice to their other characteristics.

    This techniques was used commercially in Canada 



    ------------------------------
    Alex Speers B.Sc. (Agr.), Ph.D.,FIBD
    Kootenay Consulting
    ------------------------------

    Original Message


  • 14.  RE: DMS Reduction in lagering beer

    Posted 03-28-2023 07:51

    According to Charlie Bamforth, and I think it is relatively widely known, Cu and Fe are ions that you do not want in your beer for staling or flavor.  Steer clear.



    ------------------------------
    D. Evan Evans
    Dr
    The Tassie Beer Dr
    Lindisfarne TAS
    61 362439556
    ------------------------------

    Original Message


  • 15.  RE: DMS Reduction in lagering beer

    Posted 03-24-2023 11:50

    Only thiols will complex with Cu ions.  DMS will not but if by circulating some off gassing occurs I can see where some volatile compounds such as DMS could be lowered

     

    Sent from Mail for Windows

     




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