Urea & nutrients
- 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).
********* SNIP **************
Date: Thu, 24 Aug 2000 14:37:10 -0400
From: "Pannicke, Glen A." <glen_pannicke@...>
>Whilst in an investigational study involving yeast nutrients, ...<snip>
> "Please inform this brewer that urea based products are banned*********** SNIP ***********
>throughout most of the World for beverage alcohol.
>They produce ethyl carbamates which are CARCINOGENIC.
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@...
- 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).
- 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 :
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