An Improved Mode of Manufacturing Yeast.
Year: 1891

page_text: Date of Application, 24th July, 1891
Complete Specification Left, 22nd Apr., 1892-Accepted, 28th May, 1892
PROVISIONAL SPECIFICATION.
An Improved Mode of Manufacturing Yeast.
I ARCHIBALD WALKER of 4 Muirhead Street in the City of Glasgow,
Distiller, do hereby declare the nature of this invention to be as follows .-
--
The chief object of this invention is so to carry on the manufacture of yeast, as
to obtain an increased yield from a given quantity of grain, and that without
interfering with the Excise regulations.
In carrying out my invention, I prepare a mash of barley malt, either green
malt or dried malt alone, or along with rye, maize, barley, oats, wheat, buckwheat,
dari, or with materials, rich in protein, such as peas, vetches, bran, malt culms,
beans, or lentils. When the wash is to be used for the production of peated malt
whiskey, I use malt which has been exposed to the smoke of peats.
The grain used depends on the variations in the market price, but I prefer to
use 50 per cent. or upwards of green malt, the rest of the grain employed being
rye, or partly rye and partly maize. The quantity of green malt is reckoned as the
weight of the barley from which it is made.
In all cases, I prefer to use a very large percentage of green malt.
Where rye is used, it is preferably moistened with cold water, and then partially
dried. When maize is used, it is ground, and heated with water for a short time.
The green malt and the softened rye are crushed between rollers, and then mixed
together with cold water, which is preferably slightly acidulated. In warm weather,
ice may be employed to keep down the temperature of the mixture, which is allowed
to stand for some hours. The mixture is then transferred to another vessel, which
is fitted with a perforated false bottom; the mash is thoroughly mixed, and the
temperature gradually raised by steam and hot water, or by the maize mash (which
is added at this point, in cases where maize is used), to a temperature of about
144° Fahr., at which it is kept for a time, sufficient to allow the starch to be
saccharified by the action of the diastase in the malt. After allowing the grain
husks and residues to settle, the liquor or wort is drained off from the grain husks
through the false bottom. The settling and straining off of the husks and grain
residues through the false bottom may, if preferred, be done in a different vessel
from that in which the mixing and heating is done. I prefer also to pass the
liquor through silk or other filtering material before it goes into the fermenting
vessel.
"
The wort is then run into the fermentation vessel, being cooled down to a
temperature of about 86° Fahr. The grain residues are washed or sparged
repeatedly with hot water, to extract the saccharine substances therefrom. The
specific gravity of the wort in the fermenting vessel must be about 1-033.
It is put in fermentation by adding about 2% of a fine quality of distiller's yeast,
which must be as free as possible from bacteria.
During the whole course of the fermentation, the wort must be kept at a
temperature of about 86° Fahr. This is accomplished either by cooling pipes
placed inside the fermenting vessel, or by means of a water jacket forming the
sides of the fermenting vessel. During the whole course of the fermentation, air
must be forced through the liquor.
At first, and when the vessel is filling, the air is pumped in, in comparatively
moderate quantities, but afterwards the speed of the air pump is increased, so that
the liquor is kept strongly agitated and thoroughly aerated. The air, which is
preferably filtered and cooled, is delivered into the liquor through perforated
pipes.
When the fermentation is nearly over, the aeration is gradually decreased, and

page_text: the liquor in the fermenting vessel is cooled down to about 50° to 60° F. The
liquor will now be found to contain a large quantity of yeast, not as a scum on the
surface, as in the usual methods of manufacturing yeast from grain, but suspended
in the liquor, and gradually settling towards the bottom.
The yeast may be separated from the liquid by allowing it to subside partially
in the fermenting vessel, drawing as much as possible of the clear liquor off the
top, and then straining, by means of a pump, the rest of the liquor through a filter
cloth placed on a perforated or corrugated plate at the bottom of the fermenting
vessel.
The yeast having been more or less completely separated from the wash, is then
mixed with water, sieved (if necessary), washed, pressed, and packed for market
in the usual way.
The wash and the yeast pressings and washings are distilled in order to extract
the alcohol which they contain.
An additional quantity of alcohol may be recovered, if the air which is forced
through the fermenting liquid is caused to deposit in water the alcoholic vapor which
is carried off.
Doted this 04th day of July 1891
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Mode of Manufacturing Yeast.
I ARCHIBALD WALKER of 4 Muirheal Street in the City of Glasgow,
Distiller, 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 :-
The chief object of this invention is so to carry on the manufacture of yeast, as
to obtain an increased yield from a given quantity of grain, and that without
interfering with the Excise regulations.
In carrying out my invention, I prepare, in a suitable vessel, a mash of barley
malt, either green malt or dried malt alone, or along with rye, maize, barley, oats,
wheat, buckwheat, dari, or with materials rich in protein, such as peas, vetches,
bran, malt culms, beans, or lentils. When the wash is to be used for the produc-
tion of peated malt whiskey, I use malt which has been exposed to the smoke of
peats.
The grain used depends on the variations in the market price, but I prefer to
use 50 per cent., or upwards, of green malt, the rest of the grain employed being
rye, or partly rye and partly maize. The quantity of green malt is reckoned as
the weight of the barley from which it is made.
In all cases I prefer to use a very large percentage of green malt.
Where rye is used, it is preferably moistened with cold water, and theu partially
dried. When maize is used, it is ground, and heated with water for a short
time.
The green malt and the softened rye are crushed between rollers, and then
mixed together with cold water, which is preferably slightly acidulated. In warm
weather, ice may be employed to keep down the temperature of the mixture, which
is allowed to stand for some hours. The mixture is then transferred to another
vessel, which is fitted with a perforated false bottom; the mash is thoroughly
mixed, and the temperature gradually raised by steam and hot water, or by the
maize mash (which is added at this point in cases where maize is used), to a
temperature of about 144° Fahr., at which it is kept for a time, sufficient to allow
the starch to be saccharified by the action of the diastase in the malt. After
allowing the grain husks and residues to settle, the liquor or wort is drained off
from the grain husks through the false bottom. The settling and straining off from

page_text: he husks and grain residues through the false bottom may, if preferred, be done
in a different vessel from that in which the mixing and heating is done. I prefer
also to pass the liquor through silk or other filtering material, or through a filter
press, before it goes into the fermenting vessel.
The wort, preferably slightly acidulated, is then run into the fermentation vessel,
being cooled down to a temperature of about 86° Fahr. The grain residues are
washed, or "sparged," repeatedly with hot water, to extract the saccharine
substances therefrom. The specific gravity of the wort in the fermenting vessel
must be about 1-033.
It is put in fermentation by adding distiller's yeast of a fine quality, in the
proportion of about 2 lbs. to every 100 lbs. weight of the grain, which yeast must
be as free as possible from bacteria.
During the whole course of the fermentation, the wort must be kept at a
temperature of about 86° F. This is accomplished either by cooling pipes placed
inside the fermenting vessel, or by means of a water jacket forming the sides of the
fermenting vessel. During the whole course of the fermentation, air must be forced
through the liquid.
At first, and when the vessel is filling, the air is pumped in, in comparatively
moderate quantities, but afterwards the speed of the air pump is increased, so that
the liquor is kept strongly agitated and thoroughly aerated. The air, which is
preferably filtered and cooled before use, is delivered into the liquor through
perforated pipes.
When the fermentation is nearly over, the aeration is gradually decreased, and
the liquor in the fermenting vessel is cooled down to about 50° to 60° F., or lower.
The liquor will now be found to contain a large quantity of yeast, not as a scum
on the surface, as in the usual methods of manufacturing yeast from grain, but
suspended in the liquor, with a tendency to precipitate.
The yeast may be separated from the liquid by allowing it to subside partially
in the fermenting vessel, drawing as much as possible of the clear liquor off the
top, and then straining, by means of a pump, part of the remaining liquor through
a filter cloth placed on a perforated or corrugated plate at or near the bottom of
the fermenting vessel.
The yeast having been more or less completely separated from the wash, is then
mixed with water, sieved (if necessary), washed, pressed, and packed for market
in the usual way.
The wash and the yeast pressings and washings are distilled in order to extract
the alcohol which they contain.
In the cases where peated malt whiskey, or Irish pot still whiskey, is to be made,
the distillation of the wash must be carried on in pot stills, but in other cases,
Coffey's still, or other economical apparatus, may be used.
An additional quantity of alcohol may be recovered, if the air which is forced
through the fermenting liquid is caused to deposit in water the alcoholic vapor
which is carried off.
The temperatures, times, and gravity herein before given, may vary somewhat
with the quality of grain and malt used. The grain and malt may be ground (instead
of being crushed), or passed through a green malt mill, and the steeping may be
curtailed, or, in certain circumstances, dispensed with altogether.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The process of manufacturing yeast as above described, and for the purposes
above set forth, and consisting in fermenting a wort (made principally or entirely
from green malt) under the influence of strong aeration, allowing the yeast to
subside in the fermenting vessel, drawing the clear liquor off the top, and
straining off part of the remaining liquor, and washing and pressing the yeast.
2. The preparation of a strong yeast for bakers from wort, suitable for the

page_text: manufacture of peated malt whiskey, by fermenting a wort made from malt which
has been exposed to the smoke of peats under the influence of strong aeration,
allowing the yeast to subside in the fermenting vessel, and separating and preparing
the yeast, substantially as hereinbefore described.
Dated this 22nd day of April 1892.
NEWTON & SON,
Agents for the Applicant.