Pils Malt and Soap

[Westco]

Has anyone ever noticed that some pils malt tastes like Soap? I never noticed it in darker lagers, but in light pilsners or kolschs I get soapy notes coming out. I thought that a recent pils I brewed had way to much starsan leftover and that may have given it a soapy flavor. it wasn't until I went over to a friends house who has been brewing for 15 years and tried his Maibock which I could pick up on soap notes in the brew. I just got back from slurp and burp's home brew competition where I got to judge many light pilsner based brews. Again the soap taste is so overpowering to me now I can't stand that style anymore.

Is there one brand of pils malt that has this flavor that I can avoid? I have been using best maltz currently but i am sure that not every beer that I got to judge uses the same malt. This is kinda driving me crazy beings I love (or use to) Pilsners. Maybe now that I know its in those beers it will just always stick out to me. I know some people can't pick it out, but most can but it doesn't seem to bother them as much as it does me. if anyone has any hints on how to get rid of this flavor in your brew or just know what the fuck I am talking about please feel free to add your 2 cents.

Westco

[brewinhard]

Soapy flavor sounds like it could be yeast related. Maybe you are tasting it more in pilsner malt based beers b/c there is less to hide behind. I can't say I have tasted that flavor before besides when my Grandmother made me wash my mouth out for swearing!

[Herr Roachmeister]

This is not experience speaking, sadly. I got that straight out of "How to Brew" by John Palmer. The cure, apparently, is more about pre-brew and racking cleanliness than anything else according to the same book.

Soapy flavors come from the fats that are salted and become, well... soap. You taste them in Pilsener beers because they are delicate beers with little else to cover the flavor.

[BDawg]

Lipids + salts == soap.

Everybody has different taste thresholds for various flavors, and you are probably one of the (unlucky) ones with a low taste threshold for this off-flavor.

1. Check your water for overabundance of salts. Try diluting with RO or distilled water.

2. Try a protein rest to reduce lipids and therefore soap production. Also, be sure to let the wort settle fully before racking to the primary fermenter, and bring only a small amount of trub with it. (Chill, then let it settle. It could take a few hours. Be patient. Be very careful to use good sanitation. If your sanitation procedures are sound, then you'll be ok.). Pitch an appropriately large cell count of healthy yeast into clear, trub free wort, and the lipid problem should go away.

HTH-

[Herr Roachmeister]

How do you aerate if you are being so gentle getting to the primary fermentor? Using artificial aeration, or a spare sanitized bucket apart from the stock pot to pour back and forth?

[ajdelange]

Assuming that the problem is not failure to rinse soap off equipment it is the result of "saponification" (literally conversion to soap) of triacyl glycerols forming an organic salt with a metal ion. The basic reaction, for a single alcohol ester (mono acyl glycerol - I made that up) is CH3OCOR + NaOH ---> CH3OH + NaOCOR in which R represents a long acyl chain from the long chain fatty acid HOCOR. In this reaction methanol is produced along with the soap NaOCOR. In the reaction with triacyl gylcerols you have three of the CH3OCOR esters linked together, it takes three alkalai molecules and instead of the simple methanol molecule a glycerine, H(CHOH)3H, molecule is produced along with 3 of the resulting salt molecules (the soap). Saponification, clearly takes place most readily at high pH (OH ions are consumed) when a metal ion is present.

So for your beer to taste soapy you need:

1) Grease (the triacyl glycerol)
2) High pH
3) Metal ions.

WRT 1: All grains contain oil to a greater or lesser extent and there isn't much you can do about it except try to get it out of the beer to the extent you can do this. Next time you brew feel some of the teig that settles on top of the grain in the lauter tun and also the hot break material in the kettle. Both are greasy. So it should be obvious that you do not want this break material to enter the fermenter. Whirlpool, use a hop back or take whatever measures are necessary to prevent this stuff from getting into the beer. There is debate as to whether the same should be the case for cold break. Most agree that it leads to soapiness but if the hot break has been managed the level should be so slight as to hardly be noticeable and, some say, the lipids in the cold break relieve the yeast of the job of producing all the lipids they need de novo.

WRT 2: Beer pH is well below the best pH for saponification (you grandmother used strong lye solution to raise pH) but the need for hydroxyl ions suggests that prevention of saponification is yet another reason to want to keep mash and kettle pH respectably low. This is conjecture. I have never seen (or if I have, don't remember) any data on saponification vs. pH.

WRT 3: While I suppose you might advance an argument that brewing with soft water denies the saponification the cations it needs the fact that malt contains quite a lot of metal tends to weaken that argument to my way of thinking.

It's already been said that healthy yeast properly managed tends to prevent problems with fermentation in general but it is interesting to consider that notoxygenating might actually help in reducing saponification beacuse the yeast would, lacking oxygen, assimilate more lipid from the wort than if oxygen is present.

FWIW I have never experienced soapy flavors in any beer I've produced and I do mostly lagers all of which contain at least some Pilsner malt. So I don't think it's something you can ascribe to Pilsner malt. I don't do anything special to minimize saponification but I do strain wort out of the kettle through the hop bed (I always have at least some leaf in the kettle for this purpose) which settles out on a false bottom and I do pay attention to pH throughout the process. I do not separate cold trub.

[Edit: left out an oxygen atom]

[ajdelange]

Thought of something else. It is well known that bisulfite interferes with the pyruvate ---> acetaldehyde + CO2 ----> ethanol pathway forcing carbon from glucose to flow preferentially down the dihydroxyacetone phosphate --> glycerol pathway. Apparently the Germans converted their brewing industry to a source of gylcerine for explosives manufacture during WW I via use of bisulfite. Were you to add a modest amount of bisulfite to yout mash you would, according to some, acheive benefits such as a lighter color and a more stable reduced state beer but you would also limit saponification via Le Chateliers prinicpal i.e. with glycerol, one of the reactants of saponification, at a higher level the reaction would be forced to the left or prevented from going so far to the right as it would otherwise: Triacyl Glycerol + Na+ + OH- <---> soap + glycerol

While this sounds interesting theoretically it is not the way to fix the problem. The way to fix the problem is to manage the fermentation properly, insure wort pH is in the proper range and remove trub.

[coffeeman]

i have also heard of soapy flavors coming from high hopping levels and hard water. perhaps adjusting the chloride to sulfate level with help (more to the sulfate).