Improvements in and relating to the Production of Yeast.
Year: 1895

page_text: Date of Application, 4th Mar., 1805
Complete Specification Left, 4th Dec., 1895-Accepted, 4th Mar., 1896
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Dr. JEAN EFFRONT, of 47 Rue de Trèves,
Brussels, in the Kingdom of Belgium.]
Improvements in and relating to the Production of Yeast.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the production of yeast, and comprises an improved
process for recovering yeast which is characterized by the production of yeast by
dregs in opposition to the processes of recovery by liquids, the yeast produced by
dregs having a much greater vitality and being adapted for use in distilleries and
breweries without any preparatory reconstitution.
The two well-known modes of producing yeast, which consist one in removing it
in proportion as it rises to the surface during the fermentation, and the other in
recovering it as a deposit after fermentation in the treatment of clear wort,
necessitate a whole series of washing operations by water and decantations before
the compression. Now experience shows that these various manipulations weaken
considerably the fermentescible power of the yeast so that, if suitable in this form
for the panification, it is no longer adapted for use in distilleries and breweries,
that is to say it is deprived of the elements essential to the vitality of the cells,
and regains its vitality only after a long series of cultures indispensable for the
reconstitution of these elements.
The mode of recovery by dregs entirely obviates these inconveniences, the yeast
thus produced determining instantly the fermentation at the moment of its
introduction into the saccharified wort.
This yeast is produced as follows:
A wort of maize, rice or other oereals in fermentation is passed at the close of
the fermentation into a filter press which keeps back the dregs wherein is retained
almost all the yeast contained in the wort. These dregs are subjected to slow
desiccation either in the open air or in a vacuum in appropriate apparatus, heated
to about 40 or 50 degrees Centigrade. The dry dregs thus obtained contain a
yeast of great vitality having the qualities mentioned and being particularly
suitable for distilleries and breweries.
This improved process of recovering yeast has not only the advantage of the
superiority of the product as regards quality, but also that of great simplicity of
production and especially that of high preservability, absolutely incomparable to
that of the yeast obtained by the ordinary processes. In fact, whereas a
commercial yeast of the best quality cannot be preserved for longer than 4 or
5 days in summer without beginning to putrefy, the yeast produced by this
improved process, that is to say by dregs, may be preserved for 3 to 5 weeks even
in the worst seasons.
It may here be observed that this yeast keeps much longer than ordinary yeast,
because in its state of dryness it is exempt from one of its destructive factors,
namely from the ferments which live to the detriment of the cells and cause the
yeast to putrefy, while it is still under the domination of the second destructive
factor of the yeast, which consists in the peculiarity that the yeast left to itself

page_text: without nutritive substances continues to live, and that the assimilation and
disassimilation are accomplished to the detriment of the protoplasmic mass so that
the indefinite preservation of the yeast can be obtained only as long as it is
protected on the other hand from the action of the ferments which pollute it,
weakening the cells, and on the other hand from manifestations of a life exerting
itself at the expense of its constituents; in other words it is necessary to bring
the cells to a kind of lethargic state during which all the manifestations of life
remain extinct.
Either of the two objects may be realized by the same preserving element or
agent in the form of an appropriate antiseptic, such as hydrofluoric acid, phenol,
corrosive sublimate, boric acid, salicylic acid or the like from the moment when,
especially for arresting the vitality of the yeast, use is made of sufficiently strong
doses of these agents. However, when realizing these conditions by the employment
of doses of antisepties necessary for obtaining this state, the vitality of the yeast
is weakened to such a point that it can scarcely be brought to life again, so that it
is important how the antiseptics are used.
It has been ascertained that as a general rule the yeast may be brought to
complete rest if instead of subjecting it once to the necessary dosing operation, it
in submitted to progressive dosing by antiseptice, thus accustoming it gradually to
their action and drying it after exposure to the maximum dose of the antiseptic
which this kind of yeast can withstand. In this manner yeast can be cultivated in
wort which is acidulated to a maximum of 100 grammes of fluorhydric acid per
hectoliter; that is to say, the yeast has still vitality and sufficient resistance in
such acidulated wort provided it (the yeast) has by progressive assimilation been
successively accustomed to withstand the above degree of acidulation, so that it
can now act without having lost any of its efficiency or fermenting capacity. This
yeast is employed in a wort dosed with 100 grammes according to circumstances,
which is caused to ferment in order to withdraw therefrom and then dry the dregs
containing the yeast.
Under these conditions all signs of life cease in the dried yeast, but the latter
immediately returns to active life as soon as it is introduced into a wort suitable
for fermentation.
By using in the same process salicylic acid the maximum dose will be
150 grammes of this acid per hectolitre, and it has been found that even when
slightly dried the yeast no longer manifests any sign of vitality.
Accordingly the improved process of recovery set forth provides for the
preparation of yeast of a particular physiological state, which may be obtained by
a whole series of antiseptics from the moment the corresponding yeast variety is
gradually caused to bear the maximum of the dose and is then dried.
In this manner yeast cultivated in the maximum of antiseptic which it is capable
of bearing and then slightly dried has been preserved for a year and a half in open
vessels without any alteration, and when put in wort has immediately caused
fermentation..
The yeast obtained by dregs possesses the same interest for the brewery, for it
is often required in this industry to preserve a yeast variety and to cause it to
undergo transports by which it is polluted.
In order to bring brewer's yeast to a great preservability it is diluted in a very
weak wort containing little sugar and much dregs; the whole is filtered together
and dried. Here as in distilleries it is preferable to first ferment the yeast in a
wort containing a certain maximum of antiseptic, cause it to undergo the dosing
operations with the maximum of antiseptic which it can bear, filter it and then
dry it as described.
Dated this 4th day of March 190K

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to the Production of Yeast.
I, HENKY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention has for its object the recovery of yeast from a wort in fermentation
by the solid portion, vis. the malt residues or dregs in opposition to the old process
of recovery by the liquid portion of the wort, this method of obtaining yeast being
much more preferable since the yeast obtained by the residues or dregs has a much
greater vitality and is adapted for use in distilleries or breweries without any
preparatory reconstitution or reviving.
The two well-known modes of producing yeast, which consist, one in removing
it in proportion as it rises to the surface during the fermentation, and the other in
recovering it as a deposit after fermentation in the treatment of clear wort,
necessitate a whole series of washing operations by water and decantations before
the compression. Now experience shows that these varions manipulations weaken
considerably the fermentescible power of the yeast so that, if suitable in this form
for bread making, it is no longer adapted for use in distilleries and breweries, that
is to say it is deprived of the elements essential to the vitality of the cells, and
regains its vitality only after a long series of cultures, indispensable for the
reconstitution or reviving of these elements.
The mode of obtaining the yeast from the solid portion or malt residues entirely
obviates these inconveniences, the yeast thus produced causes instantly fermentation
at the moment of its introduction into the saccharified wort.
This yeast is produced as follows:
A wort of maize, rice or other cereals in fermentation is passed at the close of
the fermentation into a filter press which keeps back the dregs or residues wherein
is retained almost all the yeast contained in the wort. These dregs are subjected
to slow desiccation either in the open air or in a vacuum in appropriate apparatus,
heated to about 40 or 50 degrees Centigrade. The dry dregs thus obtained contain
a yeast of great vitality having the qualities mentioned and being particularly
suitable for distilleries and breweries.
This improved process of obtaining yeast has not only the advantage of the
superiority of the product as regards quality, but also that of great simplicity of
production and especially that of high preservability, absolutely incomparable to
that of the yeast obtained by the ordinary processes. In fact, whereas a
commercial yeast of the best quality cannot be preserved for longer than 4 or
5 days in summer without beginning to putrefy, the yeast produced by this
improved process, that is to say by dregs, may be preserved for 3 to 5 weeks even
in the worst seasons.
It may here be observed that this yeast keeps much longer than ordinary yeast,
because in its state of dryness it is exempt from one of its destructive factors,
namely from the ferments which live to the detriment of the cells and cause the
yeast to putrefy, while it is still under the domination of the second destructive
factor of the yeast, which consists in the peculiarity that the yeast left to itself
without nutritive substances continues to live, and that the assimilation and
disassimilation are accomplished to the detriment of the protoplasmic mass so that
the indefinite preservation of the yeast can be obtained only as long as it is
protected on the one hand from the action of the ferments which pollute it,
weakening the cells, and on the other hand from manifestations of a life exerting
itself at the expense of its constituents; in other words it is necessary to bring

page_text: the cells to a kind of lethargic state during which all the manifestations of life
remain extinct.
Either of the two objects may be realized by the same preserving element or
agent in the form of an appropriate antiseptic, such as hydrofluoric acid, phenol,
corrosive sublimate, boric acid, salicylic acid or the like from the moment when,
especially for arresting the vitality of the yeast, use is made of sufficiently strong
doses of these agents. However, when realizing these conditions by the employ-
ment of doses of antiseptics necessary for obtaining this state, the vitality of
the yeast is weakened to such a point that it can scarcely be brought to life again
so that it is important how the antiseptics are used.
It has been ascertained that as a general rule the yeast may be brought to
complete rest if instead of subjecting it once to the necessary dosing operation,
it is submitted to progressive dosing by antiseptics, thus accustoming it gradually
to their action and drying it after exposure to the maximum dose of the antiseptic
which this kind of yeast can withstand. In this manner yeast can be cultivated in
wort which is acidulated to a maximum of 100 grammes of fluorhydric acid per
hectoliter that is to say, the reast has still vitality and sufficient resistance in
such acidulated wort provided it (the yeast) has been recovered by the dregs from
worts having progressively been assimilated with a stronger dose of antiseptic, so
that the obtained yeast has been progressively accustomed to the said degree of
antiseptic and is now able to withstand the desired degree of acidulation of the
wort and to act in it without having lost any of its efficiency and fermenting
capacity. If the antiseptic proportion was of 100 grammes at the last degree of
assimilation, the obtained yeast may be, employed in a wort dosed with 200 grammes
or somewhat less, which is caused to ferment in order to withdraw therefrom and
then dry the dregs containing the yeast. Under these conditions all signs of life
cease in the dried yeast, but the latter immediately returns to active life as soon as
it is introduced into a wort suitable for fermentation.
By using in the same process salicylic acid the maximum dose will be 150 grammes
of this acid per hectolitre, and it has been found that even when slightly dried the
yeast no longer manifests any sign of vitality.
Accordingly the improved process of recovery set forth provided for the
preparation of yeast of a particular physiological state, which may be obtained by
a whole series of antiseptics from the moment the corresponding yeast variety is
gradually caused to bear the maximum of the dose and is then dried.
In this manner yeast cultivated in the maximum of antiseptic which it is capable
of bearing and then slightly dried has been preserved for a year and a half in open
vessels without any alteration, and when put in wort has immediately caused
fermentation.
The yeast obtained by dregs possesses the same interest for the brewery, for it
is often required in this industry to preserve a yeast variety and to cause it to
undergo transports by which it is polluted.
In order to bring brewer's yeast to a great preservability it is diluted in a very
weak wort containing little sugar and much dregs; the whole is filtered together
and dried. There as in distilleries it is preferable to first ferment the yeast in a
wort containing a certain maximum of antiseptic, cause it to undergo the dosing
operations with the maximum of antiseptic which it can bear, filter it and then
dry it as described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. Process of preparing yeast called dregs yeast, the characteristic feature
being the recovery of the yeast from a fermented wort by retaining it with the
said portion or dregs by filtration and desiccation.
2. The preparation, according to the process described in the first claim,
of dregs-yeast of a particular physiological character and of an absolute

page_text: unchangeability, the essential feature being the recovery and the desiccation of the
dregs of antiseptized and fermented wort by the yeast accustomed to antiseptic
doses progressively increased to the maximum amount which these yeasts are
capable of bearing.
"
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
100GX 100 TO CAN THAT STITO TORST