using slippery elm
to prevent oil rancidity...
So, I was up the other night, herb-nerding out by randomly
browsing through King's American Dispensatory, hoping to
find something profound, when I stumbled across the entry
Ulmus fulva (slippery
elm). It's an herb I've always thought of as rather
straight forward: useful, mostly, as a protective,
nutrient rich mucilage for dry and enflamed digestive
problems. But I figured I'd see what King's had to
...and, look what I found, not under "Action, Medical
Uses, and Dosage", but under "Chemical Composition":
"Dr. C. W. Wright states that, when
fatty substances are heated for several minutes with
slippery-elm bark, in the proportion of 1 part of the bark
to 128 parts of the fat, and then the fat be removed by
straining, this has acquired the property of not
undergoing rancidity (Amer. Jour. Pharm., 1852, p. 180)."
Wow... that's rather fascinating...
I inquired on Henriette Kress's
herblist, and was
delighted to get a reply back from Susan Strasser (who I
had the pleasure of meeting and sharing a nice lunch &
nicer conversation with at the International Herb
Symposium), who wrote back, saying, "I have the AJP from
1852 from the American Periodical Series, a database that
the university I work for subscribes to. Here's the gist
of the article, reprinted from the Western Lancet:
"Charles W. Wright, MD, of
Cincinnati was talking to an early settler about what the
Indians living there used to do, and mentioned that they
had preserved bear's fat by frying it out, then melting it
again with slippery elm bark, "finely divided," either
fresh or dry, about one drachm of bark to a pound of fat.
"When these substances are heated together for a few
minutes, the bark shrinks and gradually subsides after
which the fat is strained off an put aside for use."
He tried it with some other fats, and says it worked every
time. "One specimen of butter, (an article which it is
well known becomes rancid sooner than any other kind of
fat,) prepared in this way more than a year ago, is as
sweet, and as free from disagreeable odor, as the day it
was made, having been exposed all this time to the
atmosphere and change of temperature. Hog's lard may be
preserved in the same manner.
This fact will be of much importance in the preparation of
cerates and ointments, which can be thus protected from
So, practically speaking,
by heating one ounce of slippery elm bark in a gallon of
oil, we can prevent that oil from going rancid; seemingly
A good night of herb-nerding, eh?