Ask The Brewmasters

 View Only

  • 1.  Extreme poor head retention on black beers

    Posted 02-28-2025 09:12

    Hi everyone.

    I've encountered in my own production and in other pubs some black beer that suddenly has this coca-cola type of foam on it. Beer is properly carbonated, but foam makes huge bubbles that collapse in a couple of seconds. This does not happens constantly, just in some batches randomly. Most probably caused by malt components that are foam negative, but I do not understand why we get it in some batch but not in others when malt bill is the same between batch.

    Any advice on process related factors that could influence promoters and detractors in malt that could affect foam?

    Thanks

     

    DOMINIC CHARBONNEAU

    VP PRODUCTION & BRASSEUR EN CHEF

     

    B 450 250-2611, POSTE 223

    SF 1 855 650-2611

    3755, RUE PICARD, PORTE 2

    SAINT-HYACINTHE (QUÉBEC) J2S 1H3

     



  • 2.  RE: Extreme poor head retention on black beers

    Posted 02-28-2025 11:11

    Proteinase A is a major contributor to foam instability since it breaks down foam positive proteins.  This gets excreted by yeast cells when they die.  Do you see any correlation with yeast health when you "randomly" see foam instability?  If I were in your shoes I'd start by looking for any correlation between yeast viability, fermentation performance, generation, time in tank before yeast is removed etc.  Pasteurization can help by inactivating this enzyme if you have the infrastructure to do that. 

    Good luck.



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

    Original Message


  • 3.  RE: Extreme poor head retention on black beers

    Posted 03-01-2025 08:03
    Hi Dominic,
    In my experience the major cause of poor foam retention is dirty glasses. Worth a check.
    However, if the problem is batch related, here is my check-list of the major foam negative factors in the brewery which you might use as an aide-memoire:
    1) Changes in mash temperature or pH.
    2) Changes to grist composition (e.g. material ratios, change in malt variety or batch).
    3) Protein rest duration.
    4) Excessive wort boiling (check duration and evaporation rate).
    5) Yeast retention time in FV (I think best practice is to remove the yeast within 24 hours after final gravity).
    6) Traces of caustic from CIP 
    7) Refiltration (if beer is filtered).
    8) Incorrect CO2 dosing (check rotameter if used).
    9) Excess foaming in FV, SV or BBT.
    10) Oil leakage into product.

    Good luck,
    Cheers,
    Chris Williams (Hoppy Bulldog, Hong Kong)



    Original Message


  • 4.  RE: Extreme poor head retention on black beers

    Posted 03-03-2025 11:49

    Hi Dominic - 

    Apologies if this is an obvious observation, but typically darker malts are typically assumed to be more foam positive. This is because the melanoidin produced during the kilning process can act as a stabilizer for the other foam-positive compounds (malt proteins, hop compounds, et. al.).

    That can actually be a problem though, jumping off item 9 in Chris' list. When there is excess foaming during beer production (kettle, krausen and other foaming in fermenter, foamy transfers, etc.), the compounds that are needed to create and maintain a stable head are used up, clumping together and falling out of the beer during maturation or getting removed during clarification.

    From your description of the bubbles forming large and falling quickly, it could be a number of things. It sounds like there is either a lower amount of foam positive compounds left in the beer (as would be the case if there is foaming in the process as I describe), or some form of foam inhibitor present (as Jason described or the dirty glassware and higher oil content Chris mentioned).

    In addition to the items listed by Chris and Jason, check if there is consistent use of defoamer being used in the kettle and FV.

    Given the inconsistency of your problem, it could be there is a change in the malt from batch to batch (look especially at the protein content on your COA's) but also check with the team to see if there when and where defoamer is being used, if at all (defoamer often gets left off of brew logs, since the production team tends to add it 'as needed'). Adding a small amount of silicon-based defoamer will actually keep more foam-positive compounds in solution, allowing them to create a stable head in the glass.

    Additionally, there are some products that can be added to finished beer that will boost head retention and appearance. This would give you the desired effect, but it's always best to properly diagnose the issue first in case it is an easy process fix.



    ------------------------------
    Alan Windhausen
    Technical Sales Manager
    Murphy & Son Inc
    Arvada CO
    ------------------------------

    Original Message


Related Content