A NEW AND IMPROVED CHEMICAL TREATMENT OF BREWERS' AND DISTILLERS' YEAST, WHEREBY A POWERFUL BAKERS' YEAST IS OBTAINED.
Year: 1879

page_text: LETTERS PATENT to Charles Graham, of University College, London, for the
Invention of "A NEW AND IMPROVED CHEMICAL TREATMENT OF BREWERS'
AND DISTILLERS' YEAST, WHEREBY A POWERFUL BAKERS' YEAST IS OBTAINED.'
Sealed the 19th Tul. 1970
ע
PROVISIONAL SPECIFICATION left by the said Charles Graham at the
Office of the Commissioners of Patents on the 22nd February 1879.
CHARLES GRAHAM, of University College, London. "A NEW AND IMPROVED
CHEMICAL TREATMENT OF BREWER'S AND DISTILLER'S YEAST, WHEREBY A POWERFUL
BAKER'S YEAST IS OBTAINED."
This Invention relates to an improved chemical treatment of yeast obtained in
breweries and distilleries, and it is based on researches made on the food conditions
requisite for a vigorous development of the yeast organisms. In the ordinary
methods for treating brewer's and distiller's yeast the yeast is more or less washed
with water to remove the bitter and other objectionable matters, and is afterwards
pressed by a Needham and Kite's filter press or other mechanical means.
Two evils attend this process :-
1st. Washing with water, which cannot be avoided, removes various mineral
salts essential to the development of the yeast when used subsequently by the
baker.
2nd. The pressing, also requisite for making a baking yeast, such as German
dried yeast, completes what the washing began, and hence the compressed cells not
only have lost various nitrogenous principles but also mineral matters necessary for
future cell growth and development.
Yeast so prepared, when mixed with flour and water by the baker, obtains some
of the food materials requisite, notably the nitrogenous and saccharine substances
made soluble in the panification process, but the mineral matters are not supplied
in sufficient quantity by the flour, and hence imperfect development of the yeast
and imperfect fermentation of the dough.
Now the mineral matters so important to the cell development of the yeast in
the baking process, and which have been lost in the washing and pressing
operations, I supply in the following manner:-
So soon as the yeast has been sufficiently purified by washing with water, or by

page_text: any other process in which water is used, and after the yeast has settled down and
the supernatant watery fluid has been run off or in any other way separated from
the yeast, I add and thoroughly intermix with the semi-fluid yeast the following
(that is to say, one or more of them, according as an examination of the yeast shall
have determined to be advisable) chemical substances in a form insoluble in pure
water :-
Phosphate of lime, phosphate of magnesia, ammonio phosphate of magnesia,
carbonate of lime, carbonate of magnesia, the acid tartrate of potash.
The phosphate of line and carbonate of lime I usually employ, the one being a
cheap and convenient source of. phosphoric acid so essential to yeast development,
the other because it neutralises and prevents the injurious consequences of acidity
in the yeast. When an examination of the yeast shows that magnesia and
ammonia are also necessary I employ the ammonio phosphate of magnesia, and
when potash is deemed necessary I add this in the form of the insoluble acid
tartrate of potash. And I add these chemical substances to the yeast in such
proportions as each case may require, and which can only be determined by experi-
ment, and one or more of them may be omitted when considered to be unnecessary.
And all of them, or one or more of them, may be added to the yeast previously to
the water or any portion of it being removed therefrom.
When the yeast has been treated as above described the water may be removed
by means of Needham and Kite's filter press or other mechanical means.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Graham in the Great Seal Patent Office on the 21st August
1879.
CHARLES GRAHAM, of University College, London. "A NEW AND IMPROVED
CHEMICAL TREATMENT OF BREWERS' AND DISTILLERS' YEAST, WHEREBY A POWERFUL
BAKERS' YEAST IS OBTAINED."
This Invention relates to an improved chemical treatment of the yeast obtained.
in breweries and distilleries, and it is based on researches made on the food
conditions requisite for a vigorous development of the yeast organisms. In the
ordinary methods for treating brewers' and distillers' yeast the yeast is more or
less washed with water to remove the bitter and other objectionable matters, and
is afterwards pressed by a Needham and Kite's filter press or other mechanical
means.
Two evils attend this process:
1st. Washing with water, which cannot be avoided, removes various mineral
salts essential to the development of the yeast when used subsequently by the
baker.
2nd. The pressing, also requisite for making a baking yeast, such as German
dried yeast, completes what the washing began, and hence the compressed cells not
only have lost various nitrogenous principles but also mineral matters necessary for
future cell growth and development.
Yeast so prepared, when mixed with flour and water by the baker, obtains some
of the food materials requisite, notably the nitrogenous and saccharine substances
made soluble in the panification process, but the mineral matters are not supplied
in sufficient quantity by the flour, and hence imperfect development of the yeast
and imperfect fermentation of the dough.
Now the mineral matters so important to the cell development of the yeast in
the baking process, and which have been lost in the washing and pressing
operations, I supply in the following manner :-
So soon as the yeast has been sufficiently purified by washing with water, or by
any other process in which water is used, and after the yeast has settled down and
the supernatant watery fluid has been run off or in any other way separated from
the yeast, I add and thoroughly intermix with the semi-fluid yeast the following,
that is to say, one or more of them, according as an examination of the yeast shall
have determined to be advisable, chemical substances in a form insoluble in pure
water :-
Phosphate of lime, phosphate of magnesia, ammonio phosphate of magnesia,
carbonate of lime, carbonate of magnesia, the acid tartrate of potash.
The phosphate of lime and carbonate of lime I usually employ, the one being a
cheap and convenient source of phosphoric acid so essential to yeast development,
the other because it neutralises and prevents the injurious consequences of acidity
in the yeast. When an examination of the yeast shows that magnesia and
ammonia are also necessary I employ the ammonio phosphate of magnesia, and
when potash is deemed necessary I add this in the form of the insoluble acid
tartrate of potash. And I add these chemical substances to the yeast in such
proportions as each case may require, and which can only be determined by experi-
ment, and one or more of them may be omitted when considered to be unnecessary.
And all of them, or one or more of them, may be added to the yeast previously to
the water or any portion of it being removed therefrom.
Although I have described the introduction of the foregoing chemical substances
to yeast after the washing process adopted to remove the bitter flavour and for
general purification, it must be understood that where such previous washing and
purification is unnecessary the aforesaid chemicals may be introduced at once to the
yeast for the stimulating effects already described.

page_text: When the yeast has been treated as above described the water may be removed
by means of Needham and Kite's filter press or other mechanical means.
Having now described the nature of my Invention, and the manner of carrying
the same into effect, I wish it to be understood that what I claim is,-
The use or employment in the manufacture of bakers' yeast from brewers' or
distillers' yeast, either before or after the same has been purified as described, of
one or more or all of the following chemical substances in a form insoluble in water,
that is to say-Phosphate of limė, phosphate of magnesia, ammonio phosphate of
magnesia, carbonate of lime, carbonate of magnesia, and the acid tartrate of potash,
or the chemical equivalent of any of them not soluble in water, which will have
the desired effect of supplying the mineral matters necessary for the perfect cell
development of the yeast in the panification process.
"
In witness whereof, I, the said Charles Graham, have hereunto set my hand
and seal, this Sixth day of August, in the year of our Lord One thousand
eight hundred and seventy nine.
CHARLES GRAHAM. (L.S.)
Witness,
HERBERT J. ALLISON, jun², of the Firm of Allison Bro³.,
Patent Agents,
41, Southampton Buildings,
Holborn,
W.C.