_An enquiry into the Volume of Malt, in order to reduce the Grist to
liquid Measure._
The gallon, by which malt is measured, though less, is nearly of the
same capacity with that, which is used for beer or water. The quarter
of malt, contains 64 gallons of this measure, and the barrel, within
the bills of mortality, according to the gauges used by the excise,
contains 36 gallons, but without the bills, 34; though the first
quantity is the measure for sale throughout the kingdom. Hence it would
appear, that proportioning the grain to the barrel of water would be
no difficult undertaking. This however is so far from being the case,
that, after having made use of several calculations to help us to the
true proportions, we shall find, they want the corroborating proofs of
actual experience, to be entirely depended upon.
The ultimate parts of water are so very small, as to make this, as well
as all other liquids, appear to the eye one continued uniform body,
without any interstices. This cannot be said of malt laying together
either whole or ground; there are numbers of vacancies between the
corns, when whole, and between the particles when ground, but for
our present purpose the volume occupied by any quantity of malt is
properly no more, than the space which would be occupied by every
individual corn, either whole or cut asunder, were they as closely
joined together as water.
To determine, with precision, the quantity of cold water to be added
to that, which is brought to the boiling point, (an act by the brewers
called _cooling in_) it is necessary to know, what proportion a quarter
of malt bears to the measure of a barrel of water. Several operations
will be found requisite to come to this knowledge; viz. to take several
gauges of different brewings, more especially in the first part of the
process; to be well acquainted with the degree of dryness of the malt
used, the heat of the first extract, and the quantity of liquor the
mash tun holds upon every inch; to find out what degrees of expansion
are produced by the different degrees of heat in the first mash, how
much less water the mash tun holds upon an inch when hot, than it does
when cold, what quantity of water is lost by evaporation, and in what
proportion at the several terms of the process. In order to put this in
practice, the gauges of the following brewings were taken.
5 quarters of malt dried to 125 degrees.
B.[28] F. G.
The quantity of water used for the first }
mash was } 12 2 3
The malt and water gauged together in }
the mash tun just before the tap was } 25, 00 inches.
set }
Allowance for the space under the false }
bottom boards of the mash tun, as near } 0, 66 inches.
as could be computed }
The goods gauged in the mash tun, after }
the first tap was spent } 15, 41 inches.
B. F. G.
First piece gauged in the copper 8 0 2
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B. F. G.
The water employed for the second mash }
was } 12 2 3
The grist gauged with this water just }
before the tap was set } 30, 62 inches.
And just after the tap was spent 15, 63 inches.
B. F. G.
The first wort consisting of these two }
pieces gauged in the copper } 21 2 0
━━━━━━━━━━━━
B. F. G.
The water used for the third mash was 8 3 6
Just before the tap was set the grist }
with this gauged in the mash tun } 24, 60 inches
And just after the tap was spent 15, 20 inches.
━━━━━━━━━━━━
B. F. G.
The water used for the fourth mash was 8 3 6
The mash gauged just before the tap }
was set } 24, 60 inches.
And just after the tap was spent } 15, 16 inches.
The heat of the first extract was 136 degrees, to which adding two
degrees, for what is lost by the tap spending, the true heat of the
mash is 138 degrees.
The first extract, before it is blended with hops, may be estimated to
be nearly as strong as a first wort of common small beer. This, when
under a strong ebullition, raised the thermometer to 216 degrees, and
seven barrels of such a wort, when boiling, occupied an equal space
with nine barrels of cold water, at the mean temperature of 60 degrees.
Now, if the degrees of expansion follow the proportion of those of
heat, the following table, constructed upon this supposition, will shew
how many barrels of cold water would be necessary to occupy the same
space with seven barrels of wort of different heats.
Degrees of heat. Barrels of cold water. Barrels of wort.
216 9,00 7
206 8,87 7
196 8,75 7
186 8,62 7
177 8,50 7
167 8,37 7
158 8,25 7
148 8,12 7
138 8,00 7
127 7,87 7
119 7,75 7
The quantity of water evaporated in a brewing, when not in immediate
contact with fire, is more considerable than it is generally
apprehended to be; after repeated trials, I have found that what was
lost in this manner amounted nearly to one fifth.
Now since the heat of the first tap was 138 degrees, and my mash tun
holds 20,25 gallons upon an inch, the following proportion may be
deduced from the preceding table.
If 8------------7----------------20,25
7,00
--------
8,00) 141,7500
--------
17,71 Gallons,
and this is the true quantity contained in one inch, at a heat of 138
degrees.
The quantity of water used for the first mash, was 12B. 2F. 3G. or 428
gallons, of which one fifth is supposed to be steamed away, when the
first liquor is gone through the whole process of the extraction: but
as the gauges of the malt and water together are taken before the tap
is set, in the beginning of the process, the whole evaporation ought
not to be deduced, and one sixth seems to be a sufficient allowance on
this account. We may therefore suppose 357 gallons to be in the mash
tun at the time of gauging, which number being divided by 17,71, will
shew how many inches are taken up by the water at that heat.
17,71)357,0000(20,15
3542
--------
2800
1771
--------
10290
8855
--------
1435
The mash gauged just before the tap was
set, 25,00 Inches.
Allowed for the space under false bottoms, 0,66
-----
25,66
Deduct the inches taken up by the water, 20,15
-----
Remainder for the five quarters of malt, 5,51 Inches.
or 1,10 inch for one quarter. This number being multiplied by 17,71,
the quantity of gallons contained upon one inch at this heat, will give
19,48 gallons for the volume of one quarter of this malt. There now
remains nothing but to bring a barrel of water of 34 gallons, under
like circumstances, as to expansion and evaporation, with these 19,48
gallons, with this difference only, that as the proportion required
is, at the time the water and malt first come in contact, and not
after the mash has been worked, a less allowance for steaming will be
sufficient, and may well be fixed at one seventh.
Gauge within the bills of Gauge without the bills of
mortality. mortality.
If 7,00 8,00 36 If 7,00 8,00 34
36 34
----- -----
4800 3200
2400 2400
----- -----
7,00)288,00 7,00)272,00
----- -----
41,14 38,85
5,87 Lost by steam. 5,55 Lost by steam.
----- -----
35,24 33,30
The barrel of water reduced; and as 19,48 gallons, under the same
circumstances, were found equal to one quarter of malt, the following
division will shew the proportion, between them.
19,48)35,2400(1,81 19,48)33,3000(1,70
1948 1948
------ ------
15760 13820
15584 13636
------ ------
1760 184
1948
------
Thus, in malt dried to 125 degrees, the quantity of 1,70 quarters is
required to make a volume equal to 34 gallons, or a barrel of water,
according to the excise gauging without the bills of mortality; and
the quantity of 1,81 quarters is required to make a volume equal to 36
gallons, or a barrel of water, according to the excise gauging within
the bills of mortality.
The more the malt has been dried, the larger the interstices are
between its parts; the quantity of water it admits will consequently be
greater than what is absorbed by such as is less dry. More of this last
malt will be necessary to make a volume, equal to that of the barrel of
water; and every different degree of dryness must cause a variety in
this respect. It will therefore be proper to repeat the operation with
a high-dried grist.
Gauges of a brewing of eight quarters of malt dried to 140 degrees.
B. F. G.
The water used for the first mash, 11 2 4
Malt and water gauged together in the } 26,25 Inches.
mash, just before the tap was set, }
Allowed for the space under the false bottom } 0,66 Inches.
of the mash tun, }
Goods gauged in the mash tun after the } 22,36 Inches
first tap was spent, }
B. F. G.
First piece gauged in the copper, 5 0 0
━━━━━━━━━━━━
B. F. G.
The water for the second mash was 11 2 4
The mash gauged just before the tap was set, 35,70 Inches.
Just after the tap was spent, 22,19 Inches.
B. F. G.
The wort made of these two pieces }
gauged in the copper, } 17 0 0
━━━━━━━━━━━━
B. F. G.
The water used for the third mash was 8 3 6
The mash gauged just before the tap was set } 31,10 Inches.
And just after the tap was spent, 21,77 Inches.
━━━━━━━━━━━━
B. F. G.
The water used for the fourth mash was 8 3 6
The mash gauged just before the tap was set } 30,50 Inches.
And just after the tap was spent 21,60 Inches.
The heat of the first extract was 142 degrees. Now, by the table of
expansions (page 256).
G.
If 8,05 7,0 20,25 of cold water, upon
700 an inch in mash tun.
-------
8,05)1417500(17,60 will be the real
805 quantity of water
----- upon an inch in the
6125 mash tun, when heated
5635 to 142 degrees.
-----
4900
4830
-----
700
B. F. G.
Quantity of water in the first mash, 11 2 4
34
----
44
33
17
4
----
395
Deduction for the evaporation at this
period, one sixth, 65,83
------
329,17 true quantity
of the water for the first mash, which must be divided by the real
quantity of water contained upon an inch in the mash tun.
17,60)329,1700 (18,70 inches taken up
1760 in the mash tun, by
------ the water used in
15317 the first mash.
14080
------
12370
12320
------
50
The mash gauged just before the tap
was set 26,25 Inches.
Allowed for the space under the false
bottoms 0,66
------
26,91
Inches taken up by the water of the
first mash 18,70
------
Space occupied by these 8
quarters of malt 8) 8,21 Inches of
------ mash tun.
Space occupied by one quarter 1,02
17,60
------
6120
714
102
-------
17,9520 Gallons of
water equal in volume to one quarter of this malt.
Excise gauge without the bills of mortality.
If 7,00 8,05 34
34
------
3220
2415
------
7,00)273,70
------
39,10 Expansion of the barrel of water,
out of which 1/7th, 5,58, is to be deducted for
evaporation. ------
Remains, 33,52 for the barrel of water reduced,
which the quarter of malt, or 17,95, is to be compared to.
Excise gauge within the bills of mortality.
If 7,00 8,05 36
36
-----
4830
2415
------
7,00)289,80(41,44 Expansion of one barrel of
2800 water,
----- 592 1/7th to be deducted for evaporation.
980 ----
700 35,52 Barrel of water reduced,
----- which the quarter of malt,
2800 or 17,95 is to be compared
2800 to.
-----
17,95)33,5200(1,86 Quantity of malt dried to 140 degrees
1795 equal to one barrel of water.
-----
15570
14360
-----
12100
10770
-----
1330
17,95)35,3700(1,97 Quantity of malt dried to 140 degrees,
1795 equal to one barrel of
------ water, according to the excise
17420 gauge within the bills of mortality.
16155
------
12650
12565
------
Having found the volume of malt at two distant terms of dryness, we
might divide the intermediate degrees in the same manner as we have
done before, could the certainty of these calculations be entirely
depended upon; but as some allowances have been made without immediate
proof, how near soever truth the result thereof may from experiments
appear, it may be proper to point out what is wanting to make our
suppositions satisfactory.
Some part of the calculation depends on the quantity evaporated; this,
in the same space of time, may be more or less, as the fire under the
water is brisk or slow, or as the weight of the atmosphere differs.
The gauges are taken at the time the malt and water are in contact,
and more or less water may be imbibed in proportion, both of the
dryness and age of the malt; water as a fluid, malt as a porous solid
body, must differ in their expansion, but in what proportion is to me
unknown; effervescence may be another cause of want of exactness; the
different cut the malt has had in the mill, its being or not being
truly prepared, and lastly the difference as to time, of the mashing or
standing of the grist, prevent our relying wholly upon the calculation.
It is, however, not improbable that some of these incidents correct
one another. Since 1,70 quarter of malt dried to 125 degrees are equal
to one barrel of water, and 1,86 quarter of malt dried to 140 have
the same volume, the difference being but 16 parts out of 100, the
whole of the error cannot be very great, and one quarter six bushels
of malt may, at a medium, be estimated of the same volume with one
barrel of water. But, as experience is the surest guide, I have, from
a very great number of different brewings, collected the following
proportions, and repeatedly found them to be true. I have added, in the
table, the weight malt ought to have, at every degree of dryness.
A TABLE _shewing the quantity of malt of every degree of
dryness, equal to the volume of one barrel of water, and
of the mean weight of one quarter in proportion to its
dryness_.
Excise gauge Excise gauge
Degree of without the bills. within the bills. Weight in
dryness. Volume of grain. Volume of grain. pounds.
Barley 80 1,56 1,59 376
100 1,62 1,63 306
105 1,62 1,67 301
110 1,65 1,71 296
115 1,67 1,75 291
Malt 119 1,68 1,79 286
124 1,71 1,83 281
129 1,74 1,87 276
134 1,77 1,91 271
138 1,80 1,95 266
143 1,83 2,00 261
148 1,86 2,03 256
152 1,89 2,07 251
157 1,92 2,11 246
162 1,95 2,15 241
167 1,98 2,19 236
171 2,01 2,23 231
176 2,04 2,27 226
With a table thus constructed, it is very easy to reduce every grist
to its proper volume of water. Suppose those of the brewings we have
already mentioned; that of the small beer consists of 6 quarters of
malt dried to 130 degrees, the proportion of which in the table is as
1,75 to 1.
Quarter of malt. Barrel of water. Malt. Water.
If 1,75 1 6 3,42.
These six quarters of malt occupy therefore an equal volume with 3,42
barrels of water. A brown beer grist of 11 quarters dried to 130
degrees; the proportion of this in the table is as 1,74 to 1.
Malt. Water. Malt. Water.
If 1,74 1 11 6,32
The volume of these 11 quarters of malt is therefore the same with
that of 6,32 barrels of water, and the whole being brought to one
denomination, we are enabled to find the heat of the first mash; but
the effervescence occasioned by the union of the malt and water must
prevent this calculation being strictly true, the consideration of
which shall take place hereafter.
The circumstances are different in the other mashes: the waters used
for these, meet a grist already saturated, and the volume is increased
beyond the quantity found for dry malt. The quantity to be allowed for
this increase cannot be determined by our former calculations, and new
trials are to be made, in order to fix upon the true proportion.
Gauging is undoubtedly the most certain method of proceeding in
these researches; but even this becomes less sure, on account of the
expansion, evaporation, effervescence, and other incidents already
mentioned.--Our errors however cannot be very considerable, when
we deduce our conclusions from numerous and sufficiently varied
experiments.
The volume of the grist of pale malt was found, after the parting of
the first extract, to be 15,41 inches, though the space occupied by
the malt, when dry, was only 5,51 inches: and the volume of the brown
grist, at the same period, was 22,36 inches, though the dry malt filled
only a space of 8,21 inches. The proportion in both these cases, and
in all those which I have tried, answers nearly to one third, so that
the volume of the grist, in the second and all subsequent mashes, may
be estimated at three times the bulk of the malt when dry, and this
is sufficiently accurate for the operations of brewing, in which, for
conveniency sake, the application of whole numbers should be effected.
As it is found, by the gauges, that the goods, after the several taps
are spent, remain sensibly of the same volume, or at least very little
diminished; may we not conclude, the parts absorbed by the water, in
which the virtue of the grain and the strength of the beer consist,
are contained in an amazing small compass? It is indeed true that hot
waters and repeated mashes do swell somewhat the hulls and skins of the
malt, but no allowance made for this increase will be sufficient, to
remove the cause of our surprise.