Blood and Sugar was Re: [Sca-cooks] kosher soda

[Terry Decker]

>How do they refine sugar with blood?
>
>Mina

Here is an answer for you from the website of the London Sugar Bakers which
can be found at:
http://www.sugarbakers.co.uk/sb3.htm

Bear


Sugar from the West Indies is packed in hogsheads, and that from the East
Indies in canvas bags, covered with matting.  These are received into the
first floor of the refinery, situate in a little above the street, where
they are broken open and unpacked by the side of a large circular vat or
cistern, which is pouring forth clouds of steam, and filling the floor with
an oppressive sickly vapour.  In this cistern, the sugar is first mixed with
water, with the addition of a small quantity of lime water and bone black.
Heat is applied by means of steam, which issues from a number of small
copper pipes, contained at the bottom of the vessel, and from this method of
applying heat the vessel is called the blow-up cistern, the steam forcing
itself by its own pressure, or blowing up, through the mixture.  The perfect
solution of the sugar is promoted by stirring with long poles.  Shortly
before the liquid has attained the boiling point it is allowed to flow along
a channel into a filtering apparatus, situated in the room beneath; on
leaving which it appears as a clear reddish syrup.

The chief object of this process is to separate mechanical impurities, such
as dust, dirt etc. from the sugar.  Until within a few years the process was
conducted in a ruder and far less direct manner.  The raw sugar, mixed with
lime-water, was heated in a large open copper by a fire from below, and when
warm a considerable quantity of bullocks’ blood, technically called spice,
was stirred in.  The serum or watery part of the blood, (consisting chiefly
of albumen, of which white of egg is a familiar example) becoming curdled by
the heat, and entangled most of the impurities floating in the solution
raised them to the surface in the form of a thick scum, which was carefully
removed.  This process was sometimes repeated two or three times, with fresh
quantities of blood, and from the scummings a low quality of sugar was
afterwards obtained.  The liquor being thus clarified, was filtered through
a thick woollen cloth, and afterwards boiled in an open copper until
sufficiently concentrated for graining.  So imperfect was this method, that,
in order to produce loaves of the finest quality, a second refining was
necessary; the loaves first produced were broken up and re-dissolved, and
clarified with white of egg; this being carefully skimmed off, a small
portion of indigo was added, the effect of which was to neutralize the
yellow colour of the syrup.  These costly methods, which of course greatly
increased the price of sugar, are now rendered unnecessary; for, in the
modern process, a clear liquor is obtained without the aid of so offensive a
substance as bullocks’ blood, a portion of which generally become entangled
with the sugar, and was not separated by crystallization.

The filtering apparatus now in use, is arranged in an ingenious manner.  It
consists of square vessels of iron, about eight feet high, connected with
cisterns above and below, and containing a number of twilled cotton cloth
tubes, closed at the lower ends, but open at the upper ends, which are
screwed into the floor of the upper cistern.  Within each tube is a bag of
cotton cloth, which, being considerably wider than the tube, hangs down in
folds.  About sixty tubes, thus arranged, are contained in each filter, so
that by this means an extensive filtering surface is obtained; the liquor
from above, having to pass through the meshes of the cloths, is strained of
most of its solid impurities, and a clear reddish syrup drops into the
cistern below.  The bags soon become clogged up, and are frequently removed
for the purpose of being cleansed.  A black viscid mud is scraped off, but,
as this contains a portion of saccharine matter, it is again boiled and
otherwise treated before it is transferred to the dealers in manure.