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Urea & nutrients

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  • Ackland, Tony (CALNZAS)
    I ve just been going through some rec.crafts.brewing posts, and found that I may have been put wrong about using urea as a possible yeast nutrient. I ll try
    Message 1 of 3 , Sep 27, 2000
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      I've just been going through some rec.crafts.brewing posts, and found that I
      may have been put wrong about using urea as a possible yeast nutrient. I'll
      try and dig around a little more to substantiate the claim that its harmful
      (I've never heard of ethyl carbamates before).

      Tony

      ********* SNIP **************
      Date: Thu, 24 Aug 2000 14:37:10 -0400
      From: "Pannicke, Glen A." <glen_pannicke@...>
      Subject: Urea

      >Whilst in an investigational study involving yeast nutrients, ...
      <snip>
      > "Please inform this brewer that urea based products are banned
      >throughout most of the World for beverage alcohol.
      >They produce ethyl carbamates which are CARCINOGENIC.

      *********** SNIP ***********


      to which a bit later this was the reply re what various nutrients might
      contain (eg is there any urea in them ?)


      *********** SNIP ***********

      Subject: Yeast Nutrient Composition
      From: Mark Evenson <wine-hop@...>
      Date: Mon, 01 Dec 1997 13:04:56 -0800

      For the person with the question on chemical composition of yeast
      nutrient: Three of the largest homebrew/winemaking wholesale suppliers
      use varying formulas in their "house brand". Your local homebrew shop
      should be able to identify their source (especially if you're willing to
      share your info).

      L.D. Carlson (Kent, OH) food-grade urea and diammonium phosphate; white
      in color with fairly large, rounded granules

      G.W. Kent (Ann Arbor, MI) these folks have two types
      - -"Nutrient" diammonium phosphate; white, small crystals similar in size
      to sugar crystals (though more long than square)
      - -"Energizer" diammonium phosphate, yeast hulls, magnesium sulfate,
      thiamine, folic acid, niacin, calcium pantothenate; small tan grains
      with some white particles visible. I believe this is from Lalvin.

      Crosby & Baker (Westmort, MA) Fermax(TM) contains diammonium phosphate,
      dipotassium phosphate, magnesium sulfate, autolyzed yeast.

      also DLB Vineyards (Westlake, OH) diammonium phosphate; white grains.

      Sorry for the delay in responding; I wanted to check with the suppliers
      listed above to get official permission to post this info. Nobody said
      "no" although if you want more detailed info (i.e., what percentage of
      each chemical) you should contact your local homebrew shop.

      To support one of my comments of 11-22-97, I haven't found yeast
      nutrient to be helpful in my fermentations when pitching *large*
      quantities of yeast (5 gr dried wine yeast/gallon). My starting SG
      ranges from 1.090 to 1.100, and ferments to dryness (0.996 to 1.002) in
      about 2 1/2 to 3 weeks. When I did use 1 tsp nutrient in a 6 gal batch
      pitching 5 gr yeast/gallon, fermentation time was still 3 weeks, and
      left a strong chemical flavor (metallic, to my tastebuds). I'd like to
      stress that I've not done side-by-side tests with yeast hulls or bee
      pollen, so I don't know how these behave. After the "test batch" came up
      with such a strong flavor of nutrient, I swore off nutrient entirely...
      Anyway, that's my nickel's worth.

      Thanks for providing the forum for discussion!

      Anne T c/o wine-hop@...
    • Tom Johnson
      Urea as in URINE.... wow must be some strong hooch. seems like regular yeasts are a better way to go although it is interesting.
      Message 2 of 3 , Sep 27, 2000
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        Urea as in URINE.... wow must be some strong hooch. seems like regular yeasts
        are a better way to go although it is interesting.


        "Ackland, Tony (CALNZAS)" wrote:

        > I've just been going through some rec.crafts.brewing posts, and found that I
        > may have been put wrong about using urea as a possible yeast nutrient. I'll
        > try and dig around a little more to substantiate the claim that its harmful
        > (I've never heard of ethyl carbamates before).
      • Tony & Elle Ackland
        Ok, I ve found a bit more out about the effect of Urea (a fertilizer, not urine ... but there is some urea in urine ....). See :
        Message 3 of 3 , Sep 27, 2000
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          Ok, I've found a bit more out about the effect of Urea (a fertilizer, not
          urine ... but there is some urea in urine ....). See :

          http://vm.cfsan.fda.gov/~frf/fc0488ur.html
          http://www.fda.gov/bbs/topics/CONSUMER/CON00193.html

          In summary ... if you use urea as a yeast nutrient, it can end up in
          producing some urethane (also known as ethyl carbamate), which in certain
          concentrations can cause cancer. The recommended limit for urethane is
          about 125 ppb (parts per billion); typically it is present in levels like
          that. Many US producers are therefore volunterily trying to reduce the
          amount present, either by not adding urea as a fertilizer to the grain
          crops, not using it as a yeast nutrient, and finding better strains of
          yeast that can deal to it. So all in all, probably best to avoid using
          urea as a nutrient for drinking alcohol.

          From the first link ...
          Some factors influencing urethane production in alcoholic beverages, such
          as the weather, are beyond human control. Others, however, can be modified.
          For instance, some wine makers used to add a substance called urea to
          stimulate fermentation. However, when urea combines with the alcohol
          produced during fermentation, it can produce urethane. Now all the major
          U.S. wineries that had used urea have eliminated it from the manufacturing
          process. Similarly, manufacturers are experimenting with different baking
          conditions for sherry to try to reduce levels of urethane. (Sherry is baked
          to enhance its flavor.) And bourbon manufacturers have found that modifying
          the distillation process can result in lower levels of urethane by removing
          more of the chemical during distillation
          Among the more widely marketed distilled spirits tested by the agencies
          (and by industry), bourbons generally contained the highest levels of
          urethane. Many bourbons contained up to several hundred parts per billion
          (ppb). According to Curtis Coker of the division of regulatory guidance in
          the Center for Food Safety and Applied Nutrition, "It appears that the
          distillation conditions, such as temperature. needed to produce the
          characteristic flavor of bourbons result in levels of urethane
          significantly higher than those found in some other distilled spirits, such
          as vodka, which are distilled under significantly different conditions."
          Vodka and gin have shown negligible amounts, if any, of urethane. Levels of
          the chemical in plum and cherry brandies varied from 200 to 12,000 ppb;
          dessert wines, such as cream sherries, contained from less than 4 ppb to
          several hundred ppb; and table wines had levels generally from zero to 25
          ppb.
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