of APPARATUS AND PROCESS EMPLOYED IN WASHING, SIEVING, COOLING, PURIFYING AND STORING YEAST FOR USE IN BREWING AND FOR OTHER PURPOSES
Year: 1883

page_text: LETTERS PATENT to Nathaniel Bradley of Chapman Street Hulme, Manchester,
County of Lancaster England Brewers' Consulting Analyst, Manufacturer of
Brewing Materials for an Invention of APPARATUS AND PROCESS EMPLOYED
IN WASHING, SIEVING, COOLING, PURIFYING AND STORING YEAST FOR USE IN
BREWING AND FOR OTHER PURPOSES
PROVISIONAL SPECIFICATION left by the said Nathaniel Bradley at the
Office of the Commissioners of Patents on the 19th December 1883.
NATHANIEL BRADLEY of Chapman Street Hulme Manchester, County of
Lancaster, England Brewers' Consulting Analyst and Manufacturer of Brewing
Materials APPARATUS AND PROCESS EMPLOYED IN WASHING SIEVING COOLING
PURIFYING AND STORING YEAST FOR USE IN BREWING AND FOR OTHER PURPOSES.
This Invention consists of an apparatus and process to purify ordinary brewers
barm (saccharomyces cerevesice) to separate and preserve the sound and useful
portions, and to remove hurtful ferments, minute cells or "small yeast" and
objectionable matter which are injurious to beer and are often associated with
Beer-Yeast.
Pressed barm or liquid barm before pressing, if not liquid enough is mixed with
water to a necessary consistency so that each gallon of the mixture shall contain
about twenty-four ounces of pressed barm: this mixture when necessary is cooled
by the addition of ice or by any other means, and is then poured into a small
chamber in the upper part of the apparatus, where it is met when necessary, with
ice and mixed by a revolving wheel or wheels faced with strips of India-rubber or
other suitable material, which scrape against a fine sieve of wire gauze.
This metal sieve is to preserve the lower sieve and keeps back bits of grit or
metal and such refuse as would tear or destroy a linen sieve or silk sieve. The
liquid barm now falls on to a specially prepared fine sieve of silk; and to cause the
barm which has deposited on the silk to pass through the silk, when not sufficiently
fluid to do so readily another roller faced with gutta percha or other suitable
material, may be occasionally moved over the silk sieve.
.

page_text: This silk sieve is in the form of a sliding drawer, the bottom of the drawer being
the silk; and the drawer catches and holds back any slimy particles of inatter,
such as insects and dust of any kind. The objectionable matter caught in the
drawer is emptied and cleaned out during the process-The liquid containing the
barm cells now thoroughly washed and divided falls through the silk sieve into a
barm-cooler.
This vessel may be either round, square, or any suitable shape, and the washed
barm and liquid may be kept to the desired temperature by the addition of pure
ice direct, or by any method of cooling which will keep the yeast pure.
For cleanliness in cooling, precipitating, and storing the barm I prefer that the
vessel should be provided with a refrigerator. This is attached to the inside a few
inches from the bottom. Although the refrigerator is fixed to one side, it can be
moved like the back of a book, and is held in a horizontal position by a chain. By
hooking up this chain the refrigerator may be lifted to any position in the cooler,
from the horizontal to the vertical
The refrigerator is attached to the inlet pipe by a movable hinge-joint, it is also
attached to the outlet pipe by another hinge-joint, and these water-tight joints are
always open, in whatever position the refrigerator may stand, and the water passes
in through one of the joints and passes out through the other joint, until the outlet
pipe is closed by a stop-tap which is placed there for that purpose
The water is supplied and cooled by an ice-box attached to the outside of the
barm cooler. This ice-box is supplied with water by a pipe perforated with fine
holes, which spreads the water supply like rain over the top of the ice, or over a
mixture of ice and salt to produce greater cold. The temperature of the barm
liquid is kept below 50° F.
At any temperature from 45° F. to 49° F. the pure yeast globules subside, whilst
the minute cells, bacteria and vibrios, being of less specific gravity float in the
liquid above the precipitated yeast. In one of the sides of the barm cooler there is
a narrow perpendicular length of glass-a water-tight window--through which
the height of the deposited barm may be seen, and at a proper time, the super-
natant liquid containing the objectionable matter may be run off by a movable
water-tight slide outside the cooler, parallel to the window. This liquid might be
run off with a syphon, but.that is objectionable for the reason that, with a syphon
which sucks under the surface of the liquid, the upper scum which is the worst
part is never removed, whilst if run off by means of a slide, through the side of the
barm cooler, the upper surface of the liquid runs away the first and cannot fall
down to the pure deposited barm. In some cases it is necessary to run off the
waste liquid from the barm cooler by means of an open pipe within the cooler and
stop-tap outside.--The inlet end of the pipe can be moved inside in the arc of a
circle, whilst the other end is attached to an elbow, inside the cooler, which acts
as a centre. This elbow-joint conveys the liquid from the inside of the cooler to
the outside by means of a pipe to stop-tap outside. The inside pipe is moved
inside by hand.-When the cover of the cooler is closed this pipe is moved from
the outside by turning a very little the tap itself. Near the tap is an outside
index with pointer or finger to indicate the position of the pipe so as to run the
liquor off to any point required.
A further description of the pipe movement may be given thus:-Let the two
sides of a right-angled triangle represent the bottom and perpendicular side of the
barm cooler. About an inch from the inside point of this angle is an elbow-
joint (a) the pipe is screwed into this elbow and is parallel with the perpendicular
side. If the pipe be moved down towards the bottom on the elbow-joint as a
centre, the liquor will run off at any level to which the pipe may move until the
bottom is reached and if the stop-tap outside has been open, the vessel is emptied.
This tap or outlet is also used for running the liquid, which contains the washed
pure barm cells, into other vessels just as it passes from the sieve or sieves to be
cooled and precipitated on other coolers not having the sieves attached. Shallow
coolers without sieves will be required where large quantities of barm have to be

page_text: purified. In shallow coolers it will be necessary to have the outlet for running off
the liquid, which contains the bacteria and objectionable matter, through a
perpendicular single pipe or a tube in telescope form, one tube working inside
another, watertight. These move inside a stuffing-box or similar arrangement
which passes through the bottom of the cooler.
The movable pipe is kept above the surface of the liquor and when required to
convey away the liquid this pipe is pressed down to the necessary depth through
the stuffing-box; and when the cooler is required to be emptied of the deposited
pure barm, if not shovelled out, the pipe is taken out leaving the space through
the stuffing-box open for outlet, and if not used for this purpose, it will serve to
carry off washings when cleaning the cooler Reverting to the beginning of the
process after the barm has passed through the silk sieve the mixture stands about
two hours. Then for the first time a portion of the supernatant liquid is run off.
Then the barm in the cooler is mixed, when necessary, with a weak solution in
water of Tartrate of Ammonia: salicylic acid or carbolic acid; suitable phosphates
and other yeast-food and this solution is added and mixed with the yeast in the
cooler and all kept at a temperature below 50° F. for the pure yeast to finally
subside that the surface liquid containing the bacteria &c may be run off.
Healthy yeast will be injured by careless washing for the reason that some of
the contents of each yeast globule absorb water and unless this water be mixed
with food suitable for the yeast, the yeast operated upon will be weakened. After
the last runnings, the subsided barm is purified and ready for use and may be kept
stored under cover in the cooler until required. The plan hitherto adopted to
purify barm has been by reproduction or budding of the cells in saccharine
solutions at low temperatures. My plan is not to ferment but to purify the barm
itself by removing the objectionable matter.-Barm has also been washed in a
crude way but no proper process nor apparatus have been to my knowledge
invented, except by me.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Nathaniel Bradley in the Patent Office on the 16th June 1884.
NATHANIEL BRADLEY of Chapman Street, Hulme, Manchester, County of
Lancaster, England; Brewers' Consulting Analyst and Manufacturer of Brewing
Materials APPARATUS AND PROCESS EMPLOYED IN WASHING, SIEVING, COOLING
PURIFYING AND STORING YEAST FOR USE IN BREWING AND FOR OTHER PURPOSES
"
33
This invention consists of an apparatus and process employed in washing,
sieving, cooling, purifying and storing yeast for use in brewing and for other
purposes The apparatus, the method, and the means are devised to purify yeast,
that is, ordinary brewers' barm (saccharomyces cerevesice), to separate and preserve
the sound and useful portions and to remove hurtful ferments, minute cells, or
"small yeast" and objectionable matter which are injurious to beer and are often
associated with beer-yeast
Pressed barm, or liquid barm before pressing, if not liquid enough, is collected
and well mixed to a necessary consistency with cold pure water, or pure wort, or
any cold liquid suitable for mixing with or for washing yeast, in a fixed vessel, or
small movable vessel, such as the can described Figure 12, so that each gallon of
the mixture shall contain about twenty-four ounces (24 oz) of pressed barm This
mixture is poured or run from the fixed or separate vessel into a small chamber or
top-sieve which is the uppermost part of the apparatus, and if in very large
quantity, mixed by a revolving wheel or wheels faced with strips of india-rubber
or other suitable material which scrape against a fine sieve of wire gauze-This
gauze may be made of copper and should have about three thousand six hundred
[3,600] meshes to the square inch-The metal sieve is to protect the lower sieve
and keep back bits of grit or metal and such refuse as would tear or injure a cloth
sieve This cloth sieve may be made of hair cloth silk cloth, or vegetable fibre-
The liquid barm now falls through the metal sieve on to a specially prepared fine
sieve of silk-I prefer this sieve to be made of that kind of silk known as
"bolting-cloth" with not less than fifteen thousand six hundred and twenty-five
[15,625] meshes to the square inch-To cause the barm, which bas deposited on the
silk, to pass through the meshes of the silk, when not sufficiently fluid to do so
readily, another roller or hand scraper (Figure 10) faced with gutta percha or
other suitable material, may be occasionally moved over the silk sieve-The
rollers are only necessary when the barm is not sufficiently dilute-This silk sieve
may be of any suitable shape-One suitable shape is in the form of a sliding
rectangular drawer or under-drawer, the metal sieve resting upon it, the bottom of
the under drawer being the silk
This silk catches and holds back any slimy or gelatinous particles of matter,
insects, and dust of any kind-The objectionable matter caught in the drawer or
silk sieve is emptied or cleaned out during the process-Another combination of a
metal sieve and a cloth sieve is shewn and described at Figure 9-This can sieve
may be used in some cases instead of the rectangular drawer or in conjunction with
one or both of the rectangular sieves.
But in each of these cases, in which a metal sieve is used in combination with a
cloth sieve, the cloth sieve may be entirely dispensed with and the metal sieve used
alone (although I prefer the combination); but when used alone, the metal gauze
should be finer and may have as many as Nine thousand eight hundred meshes to
the square inch [9,800].
The liquid containing the barm cells now thoroughly washed and divided falls
through the sieve or sieves into a vessel containing a window or windows in its side
or sides-This vessel is the same whether called Barm-cleanser, Barm-cooler, or

page_text: Barm-purifier. This cleanser in which the washed barm is precipitated, may be
either round, square, rectangular, or any suitable shape, either of small or large
area; and is generally about eight inches deep-It may be made of wood or slate or
any suitable material-The washed barm and liquid I prefer to be about six inches
deep in the cleanser to start with and the mixture may be kept at any desired
temperature by the addition of pure ice direct or by any method of cooling which
will keep the yeast pure For cleanliness in cooling precipitating cleansing and
storing the barm, this cleanser should be provided with a refrigerator or metal
coil The coil or cooling arrangement may take any shape or movement, so that it
can be applied or moved to cool on or near the surface of the yeast mixture-I prefer
the shape shown in the diagram (Figure 1.)-This is attached to the inside near the
bottom, and although the refrigerator is fixed to one side, it can be moved like the
back of a book and held in a horizontal position by a chain or any suitable holder-
By hooking back this chain the refrigerator may be lifted to any position in the
cleanser from the horizontal to the vertical-The object and principle of this
refrigerator is to cool the liquid from the surface downwards-As the surface
liquid cools it grows heavier; the heavier yeast cells fall to the bottom and cause
the under liquid to rise and bring the more buoyant hurtful ferments to the
surface to be run off-The refrigerator is attached to the cold-water-inlet-pipe by a
movable hinge-joint or swivel-joint (×); it is also attached to the outlet pipe by
another similar hinge joint-These water-tight joints are always open in
whatever position the refrigerator may stand; the water passes in through
one of the joints and passes out through the other joint until the outlet
is closed by a stoptap which is placed there for that purpose-The water
is supplied and cooled by an ice-box attached to the outside of the barm-
cleanser This ice-box may be supplied with water by a tap or hose-The
temperature of the barm liquid is best when kept below fifty degrees Fahrenheit
(50° F) but ordinary brewers barm may be purified sufficiently for pitching with,
without ice, if cold well water can be obtained to pass through the refrigerator. At
any temperature from 40° F to 48° F the pure yeast globules subside most quickly,
whilst the minute cells, bacteria, and vibrios-hurtful ferments-being of less
specific gravity float for a time in the liquid above the precipitating yeast-In one
or more of the sides of the barm cleanser or yeast-purifying vessel there is a narrow
perpendicular length of glass-a watertight window-through which the height of
the subsiding barm may be seen; and at a proper time the supernatant liquid
containing the objectionable matter may be run off by a movable watertight slide
outside the cleanser, parallel to the window-This liquid might be run off by means
of an ordinary syphon but that is objectionable, for the reason that with a syphon
which sucks under the surface of the liquid, the upper scum which is the most
impure part is never removed whilst if run off by means of a slide through the
side of the barm-cooler the upper surface of the liquid runs away first and does not
fall down to the pure deposited barm. (A movable floating syphon might be used,
the short arm to suck from a floating basin which collected the surface liquid.)-In
most cases it is necessary or more convenient to run off the waste liquid and scum
from the barm cleanser by means of a pipe and float within the cleanser and this
pipe and its arrangements I prefer in the shape of a right-angle which passes
through the side of the cleanser and terminates outside in a stoptap or tube without
a stoptap The angle of this pipe is inside the cleanser and consists of an elbow-
joint (a.. Figure 6) into which are screwed the inside portion of the pipe at D and
the other portion of the pipe which passes straight out to F-The inlet end of the
pipe (C) when uncoupled from the float A. B., can be moved by hand inside the
cleanser up and down in the arc of a circle, the elbow joint (a) acting as a centre;
and when the top of the cleanser is covered this pipe can be moved, inside the
cleanser, from the outside-by moving round that projecting part of the pipe which
terminates at F and in which the stoptap is fixed (Figure 5)-Near this tap there
may be an outside index with pointer to indicate the position of the inside pipe so
as to run the liquor off to any point required; but I prefer the pipe to be so fixed

page_text: that as the pipe moves it shall pass before the window (figure 4) so that its
position may be seen without referring to any index-A further description of the
pipe movement may be given thus:-Let the two sides of a right-angled triangle
represent the bottom and perpendicular side of the barm-cleanser Near the inside
point of this angle is an elbow-joint a―The inlet portion of the pipe is threaded
at one end so as to screw into this elbow at D, and when screwed in it is parallel
with the perpendicular side of the cleanser―This portion of the pipe may be screwed
in or out of the elbow-joint as desired-When screwed fast in, it may be moved
towards the bottom and the liquor run off at any level to which the inlet pipe may be
moved, until the bottom is reached; then if the stoptap outside has been open, or if the
pipe has no stoptap, the vessel is emptied-When this [inner] portion of the pipe is out,
that is, when it is not screwed into the elbow-joint at all, the hare elbow-joint may
be used for running liquid through it into other vessels-Also into this elbow joint
instead of the pipe taken out a pipe with fixed float may be screwed as shown in
figure 6-This pipe which passes through the float carries off the surface scum
as fast as it is formed-But instead of taking out the pipe to substitute a fixed
float I prefer that a loose float shown in Figure 6 × should be coupled or
uncoupled at will to the pipe itself—The pipe must be made of proper length and
have a wire soldered on to pass over the cap at C and to couple or thread into the
eye on the float at B-Figure 6 x-float and pipe-is the simplest, quickest and
most suitable arrangement to carry off the hurtful ferments and scum as fast as
thrown up or before they can again deposit and I prefer this arrangement to any
other because it is self acting.-Additional shallow cleansers coolers or precipitating
vessels (Figure 7) but with neither refrigerator nor ice-box will be required,
especially so where large quantities of barm have to be purified-The sieves may
be removed from one vessel to another; or a hose-pipe may have its outlet end
fitted with sieve or sieves and the liquid barm may be conveyed from any mixing
vessel so that the washed barm may fall through the sieve or sieves direct into the
purification vessel cooler or cleanser; or a sieve can (Figure 9) may be used; but
I prefer the rectangular sieves (Figure 3)-The necessary temperature may be
obtained by a movable cooling arrangement or by ice direct, or the purification
may be performed at the ordinary temperatures of the supply water-from a well-
In all the cleansers or purification vessels it will be necessary to have at least one
outlet, direct through the bottom, for running off the refuse liquid which contains
the bacteria and objectionable matter-This outlet may be a perpendicular single
tube which can be moved up and down through the bottom of the cooler, inside a
stuffing-box fixed water-tight or similar arrangement-This pipe or tube is always
perpendicular and may be, in some cases, fitted with a collecting dish so as to
obtain a greater collecting area, in order that the scum when ready for running
may be run off more quickly. This collecting-dish has a very short tube
projecting from its base, which short tube fits telescope-like and watertight
into the perpendicular tube; but so that the collecting-dish can be put on or off
at will The perpendicular tube is kept above the surface of the liquid until
required to convey the liquid away, when it is pressed down by hand through the
stuffing box to the necessary depth in the liquid-When the cooler or other vessel
is required to be emptied of the deposited pure barm, if not shovelled out, the
perpendicular pipe is drawn by hand through the bottom or pulled out upwards,
leaving the space through the stuffing-box open for the barm to pass out; and
when the outlet is not used for this purpose, it may be used to carry off
sweepings and washings; that is to say, it may be used as an ordinary outlet
with a plug or stopper-To a large cooler or cleanser, say, twelve feet long, six
feet wide and eight inches deep (Figure 7), it may be necessary to fit in the
bottom two of these stuffing boxes so that two perpendicular pipes may be in use;
and in these large vessels the space may be divided as shewn in the diagram
(Figure 7) with narrow laths about two inches high upon which to steady a
squeegee when cleaning or skimming off the top of the deposited pure barm-
But in all the purification vessels I prefer the supernatant liquid to be carried off

page_text: by a suitably sized float and pipe and in these cases the stuffing box must be used
as barm outlet with plug. The squeegee is constructed with screw arrangement so
that when the squeegee rests on the laths the rubber part which skims the barm
may be screwed down to the exact surface of the deposited barm-In most cases it
will not be necessary to use a squeegee, especially so if the purified yeast has to be
used immediately-The end of the cleanser can be elevated a few inches-by
means of a swing leg placed underneath which falls into position as the end is
elevated until the remaining supernatant liquid has run down to the other end
where the plug outlet will draw it off without the use of a squeegee.
Reverting to the beginning of the process; two gallons-or where no ice is used
three gallons of water should be added to ten pounds of unpressed yeast, or to
from three pounds to five pounds of pressed yeast-Also, when no ice is used, about
a quarter of an ounce (½ oz) of salicylic acid should be added to every 30 gallons
of the yeast mixture and the whole thoroughly mixed in the can (Figure 12).
When no ice is used the time required for precipitating the yeast is just double-
After the barm has passed through the sieve or sieves, the mixture in the cleanser
is allowed to rest undisturbed for two or three hours; then the float (Figure 6 ×)
is coupled to the pipe and adjusted with a weight so that the running will be just
so slow that there will be always about half an inch in depth of the surface liquid
above the deposited pure yeast-When the float has been running for about three
hours, the barm in the cleanser is sufficiently purified for pitching-After the
mixture has been at rest for three hours if the float or self acting arrangement be
not used a portion of the supernatant liquid containing the hurtful ferments must
be run off by working the outlets by hand, down to the level where the healthy
barm cells have deposited; the window in each cleanser showing the depth or
quantity to be run off and this process must be repeated until all the best of the
yeast has deposited-The remainder may be then mixed with preservative yeast
food (yeast nourishment) or the mixing may be delayed until just before pitching-
A perfect preservative yeast food should contain nitrogen phosphorus potash lime
and magnesia and an excellent yeast nourishment may be made as follows:-
Tartrate of ammonia three parts; rye flour, two parts; phosphate of lime, one
part; sulphate of magnesia one part; phosphate of potash, one part; carbonate of
magnesia, one part; argol, one part; total, ten parts-Two ounces (2 oz) of yeast
nourishment should be added for every 10 lbs of yeast used at commencement-A
little water (or, if used just before pitching, warm wort) is added to the yeast food,
stirred well together, and the whole thoroughly mixed with the barm liquid in the
cleanser-I do not in every case mix the yeast liquid with all the above ingredients
nor always in the above proportions; the special quality or nature of the yeast
operated on may determine the kind of yeast nourishment required-Healthy
yeast will be injured by careless washing for the reason that some of the contents
of each yeast globule absorb water, and, as a consequence, the interior constituents
of each yeast globule more or less dissolve, and unless the yeast be mixed with
suitable food, the yeast operated upon will frequently be weakened-It is therefore
a part of my process to add to the yeast when necessary, yeast food mixed with
liquid to supply those constituents which may be more or less absent from the yeast
- This makes the yeast better for pitching with and causes it to be sounder and
better after being pressed and dried-When the surface liquid is removed the barm
is sufficiently purified for pitching and if it be required immediately it should be
mixed in the purifying vessel.or cleanser with a little warm wort until the
temperature is raised to about 60° F then the whole may be removed from the
cleanser for pitching-If not required for immediate use it should be kept in
the cleanser, and covered, so as to be free from light from dust and from stench;
and the coil should remain in action with cold water passing through it to keep the
yeast cool: or it may be pressed for store barm-When prepared for sale, after
pressing the purified yeast, I dry it in a current of air not exceeding 80° F.-The
plan hitherto adopted to purify barm has been by reproduction or budding of the
yeast or barm cells, in saccharine solutions at low temperatures-My plan is not to

page_text: ferment or make barm but to purify and strengthen the barm itself and to remove
objectionable matter-Barm has also been washed in a crude way but no proper
process nor apparatus have to my knowledge been invented except by me.
In order that my invention may be more fully understood, I hereto annex
two sheets of drawings illustrative thereof and the following description of the
diagrams:-
--
Figure 1. Plan of yeast purifying apparatus-scale 11 inches to the foot.
Figure 2. Section through the apparatus on the line A. B. with sieves removed
and showing special movement of the refrigerator-1 inches to the foot.
Figure 3-Section through sieves in the line C D.-1 inches to the foot.
Figure 4-End elevation of yeast purifying apparatus showing the special
movement of the tap and elbow pipe-1 inches to foot.
Figure 5. Sectional view of tap and elbow pipe on the line E F. (3 inches to
foot).
Figure 6. Float and pipe in one piece-three inches to foot.
Figure 6x represents a loose float coupled to the pipe (three inches to foot)
-At point B there is a pin on which small weights are threaded to adjust the
float and sink the inlet end of the pipe to the necessary depth in the liquid-At the
end of the inlet pipe at C is a movable cap (see Fig 11)-Instead of the movement
in the pipe from C to F, A swivel joint might be fixed at D similar to the joint
of the refrigerator.
Figure 7. Plan of additional barm cleanser barm cooler or purification vessel
with two perpendicular tubes in stuffing boxes-At CD are the movable sieves―
One inch to the foot.
Figure 7 x. Plan of loose float and pipe similar to Figure 6 x
Figure 8. End elevation of yeast purification vessel showing the legs which are
constructed to screw in and out to suit the floor so that the vessel may rest steadily
on an uneven floor (one inch to foot)
Figure 9. Two views of yeast can with combination sieves-Metal sieve at A,
cloth sieve at B; (three inches to foot.)
Figure 10. Small squeegee.
Figure 11. Cap which fits on the end of pipe at C (Figure 6×) to regulate the
rate of flow of liquid-That part of the cap at E generally sinks in the liquid-
1 inches to foot.
Figure 12. Plan of yeast mixing vessel with mixer inside-The inside diameter
of the vessel is about half an inch greater than diameter of mixer-1 inches to
foot.
Figure 13 Elevation of the can and the mixer-The mixer is shown by the dotted
lines; it is a circular piece of wood, about two inches thick, flat on the bottom and
bevelled on the top side so that the fluid will run off into the can as it is lifted out
of the liquid-When this mixer is moved up and down the barm and liquid have
to pass through about a quarter of an inch of space between the edge of the mixer
and the inside of the can, and this mixes and washes the yeast thoroughly-
Whilst pouring from the can, the mixer floats on the yeast liquid to allay froth and
to burst gas or air-bubbles-The outlet from the can inside is purposely made
near the bottom so that in pouring on to the sieves the mixture is drawn from
below the surface, beneath the float, to avoid froth-1 inches to foot.
Having thus described my apparatus and process for purifying ordinary brewers
barm, how to remove hurtful ferments and to separate and preserve the sound
and useful portions, I do not confine myself rigidly to the use of the means herein
described as similar means may be employed for the purpose; but what I
claim is :-
Firstly A vessel containing a window or windows in its side or sides in which
to mix yeast with liquid and preservative materials for the purpose of purifying
and nourishing ordinary yeast.
Secondly The method and means of treating brewers yeast with or without ice
in the manner and for the purposes as substantially hereinbefore described.

page_text: Thirdly The use of a can (or other vessel) and mixer to mix yeast and liquid
together, to wash the yeast and to allay the froth; of the kind and for the
purposes as substantially herein described
Fourthly The use of sieves in combination or of a metal sieve alone (to sieve
the yeast mixture) of the kind and for the purposes as substantially hereinbefore
described
Fifthly to cool yeast and to hasten the subsidence of yeast which has been
prepared for purification, by means of a refrigerator or a fixed or a movable cooling
arrangement devised to cool on or near the surface of the yeast mixture in the
manner and for the purposes as substantially herein before described.
Sixthly The removal of the washings or supernatant liquid or scum from the
subsided or subsiding yeast by means of a self-acting float and pipe arrangements
fixed or movable substantially as bereinbefore described
Seventhly The addition of yeast food to the yeast liquid to supply those
necessary constituents which may be more or less absent from the yeast as
substantially hereinbefore described
In witness whereof I the said Nathaniel Bradley have hereunto set my hand and
seal this tenth day of April in the year of our Lord One thousand eight hundred
and eighty-four.
NATHANIEL BRADLEY (L.S.)