protease enzyme

Discussion in 'The Beer Forum' started by Alan Ball, Nov 17, 2017.

  1. I have just had a beer which lists one of the ingredients as protease enzyme. I have never seen this before. This appears to be an enzyme that breaks down proteins in the brewing process. I would have thought this enzyme would occur naturally as part of the brewing process. Perhaps Kinley could throw some light on this.
  2. Hopefully I can.

    Protein is a pest in beer and it is what makes beer. We need protein for head retention and body and most of this comes from the malt. The problem is that we also have polyphenols (proline-rich enopeptides) that arise from grain and hops. Polyphenols combine with protein at cold temperatures to give a chill haze which disappears when the beer is warmed (although permanent binding can occur with time). Drinkers (generally) don't like hazy beer mistaking it for yeast. Protein provides nitrogen so is needed for yeast growth and has to be present at the start of fermentation (or nitrogen has to be added as ammonium salts). But depending on the malting process, there can be increased production of the polyphenols. Typically the longer the malting process, these are more readily degraded, reducing problems. There is a trend to use the minimal malting possible which produces 'lager' malt (you can brew perfectly good beer with a lager malt; it's just a name). Commercially it makes sense and with modern analysis of malting this can be controlled very tightly, but not completely and we still see polyphenols extracted in the mash and boil. In the boil protein is precipitated when hot (hot break) using copper based proteins (Irish moss, Protofloc). We then use crash cooling ('cold break') to reduce it further but that's not enough (and we still want nitrogen for our fermentation). After fermentation, these polyphenols will settle with time (cask conditioning) or deep cooling (lagering) allowing removal, but that's expensive. So proline-specific endopeptitdases are often added at the start of fermentation allowing the time consuming steps to be skipped as well as the expensive process of protein filtering. The reduction in beer held in the brewery during filtering also increases the brewing capacity on the same plant. From the environmental side, the use of water and CO2 is greatly reduced.

    An for me, a helpful side effect is that the gluten epitope is destroyed, although the beer must be tested before it can be called gluten free.
    Antti Jokinen likes this.
  3. Delighted to find this enzyme is readily available to home brewers. I will be launching into a festival of brewing this weekend and getting my first taste of cask-conditioned ale in 6 months, in a month.
  4. Hello Kinley

    Going back to your first reply " After fermentation, these polyphenols will settle with time (cask conditioning) or deep cooling (lagering) allowing removal, but that's expensive." Are protease enzymes being used to cut corners in beer production? Shouldn't good lager be cold-conditioned for a long period anyway? Does cask-conditioned ale not require protease enzymes to be used?

    I remember reading somewhere that most of the gluten was removed in the brewing process. Is this only the case if protease enzymes are used?
  5. Sorry for the slow reply; missed this.

    1) Yes, basically. Most bottled beers are not bottle conditioned and brewers want the beer clear and in bottle ASAP. In most cases the beer for bottling is not cask conditioned. Protease speeds this up to a few days, saving a lot of time. Lager should be cold conditioned as it is so important in developing flavour. However this is a hugely costly process and most lager is rushed out the door. Even Pilsner Urquell has steadily cut the length of lagering.

    2) Cask conditioning is a highly complex process that I suspect we only know a little about what happens. Yes we see the clearing process which is the sedimentation of yeast and protein. There are studies looking at the reduction in gluten in cask beers and it is quite common from the level to fall below the 20ppm considered immunogenic to those who are coeliac (although any disturbance to the sediment could reverse this). Cask conditioning also allows the yeast to convert higher order alcohols, altering the flavour profile (and maybe taking the edge off a hangover..). However I strongly suspect there are non-enzymatic reactions that alter other aspects of the flavour. No protease need be used but finings (egg white, isinglass etc) are often use to promote sedimentation. I suspect that the protease will have little effect on the cask conditioning process.

    3) In the brewing process, most of the protein is indeed removed. In the 'hot break' boiled proteins change structure and precipitate. In the 'cold break' copper containing compounds (Irish Moss, Protofloc) are used to promote protein precipitation as the beer is cooled. During the run off most of this protein is trapped by the hops and left in the boiler. However enough protein remains in solution to retain significant gluten going into the fermentor. The protease is added at the beginning of fermentation.

    NB my first brew with the protease enzyme is a golden ale packed with Centennial, Cascade and Nelson Sauvin hops, @ 4.0% ABV. Just had its first week of cask conditioning and I can report that even now it tastes superb. Will test it for gluten in a couple of weeks.

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