Page 17 - Vol.39-No.8 issue

CROP PROTECTION

COCOA PROCESSING AFTER

ROASTING. PART 1 GRINDING

loss of cocoa butter for the latter, it is not much easier to reduce particle size when the
difficult to see why chocolate manufactur- butter is still contained in the cocoa liquor
ers generally prefer to roast beans while and the smaller the particle size the easier it
processors opt for nibs. is to extract the cocoa butter. Cocoa liquor
Roasting, which is the application of may be subjected to hydraulic pressing or
intense heat over an extended period of expeller extrusion and which release some
DR. TERRY MABBETT time (100-140°C for 45-90 minutes) is cocoa butter to leave a residue, which is
called cocoa ‘cake’.
a multifunctional process. It develops fla-
vour, accentuates colour, reduces acidity Alternatively it may be used in its own
During the long haul from cocoa tree to and astringency, decreases the moisture right to start the chocolate manufactur-
chocolate bar processing choices have to content and facilitates the easy removal ing process. Supplementary cocoa butter
be made. What type of fermentation and of the shells after bean roasting. must be added further ‘downstream’ in the
for how long and whether beans are dried chocolate manufacturing process. Liquor
naturally or artificially. For cured beans The roasted beans, now full of colour used as a base for chocolate manufacture,
arriving at the roaster, dried to 7.5% w/w and flavour, are ‘kibbled’ (cracked) in a mill need not be ground so finely. In fact a larger
moisture content and packed with the pre- to separate the shells from the ‘nib’ (the particle size can contain less cocoa butter
cursor chemicals of the flavour and aroma roasted cotyledon or kernel). ‘Kibbling’ is and still give the right mouth sensation of
compounds, there is still a long way to go. followed up with a fanning (blowing) pro- finished chocolate, an important cost re-
And there are more choices to be made. cess called ‘winnowing’, commonly used in duction consideration for manufacturers.
crop commodity cleaning. Winnowing is a
The first relates to whether whole, in- standard mechanical separation technique There is much discussion but little pro-
tact beans are roasted, or whether they are and relies on the part to be removed (the gress on where grinding is best placed.
shelled first and then roasted as cocoa nibs cocoa bean shell) being smaller and lighter Should the bulk continue to take place in
(bean cotyledon or kernel). Choices made than the part to be retained (the roasted North America, Europe and other so called
will determine the progress and character cotyledon or ‘nib’). developed countries where the big choco-
of the roast and yield of cocoa butter. late manufacturers are located, or should
Bean roasting offers more flexibility in the Grinding an increasing proportion be conducted in
degree of roast and evolution of flavour, ‘Nibs’ whether roasted as such or ob- cocoa producing countries as so-called ‘ori-
but requires more uniform bean size in the tained by de-shelling roasted beans are the gin grinding’. The latter, say proponents, will
batch. Nib roasting gives a more even and resource for the next stage called grinding. boost added value for producer countries,
balanced roast, and therefore does not Cocoa nibs are crushed at relatively high most of which are categorised as devel-
demand the same evenness of size. temperature (50 to 70 C) in cylindrical oping nations from both the technological
o
Removal of the shell prior to roasting grinders, which move increasingly closer and economic points of view.
prevents migration of valuable cocoa butter together. This ruptures the cell walls and Considerations, both economic and tech-
from the bean and into the shell during releases the cocoa butter contained therein. nological, that prevent producer countries
roasting and is, therefore, a significant Heat generated by the grinding process from competing successfully in the ‘cocoa
factor in overall yield. Given the pros and causes the cocoa butter to melt, which is grinding’ market are deep and far-reach-
cons of bean and nib roasting, which focus why the substance obtained is commonly ing. But there are several salient factors
on flexibility of roasting in the former and called the cocoa liquor or chocolate liq- relating to the commodity itself, that go
uor. But this valuable intermediary product deep and damaging against the cause for
with a cocoa butter (fat) content of 55- ‘origin grinding’.
58% goes under several different names
including ‘cocoa paste’, ‘cocoa mass’ and •Cocoa requires a hot tropical climate to
‘chocolate paste’. produce high yields of healthy fresh beans.
But once cured (fermented and dried), a
Grinding is simply the use of physical tropical climate is the worst possible loca-
force to reduce the nibs to a small parti- tion for bean storage.
cle size. But the degree of force used and
consistency of ‘liquor’ thus obtained will •Cured cocoa beans are ‘all things to all
depend on the next-stage use of the liq- men’. They are easy to ship and are ac-
uor and the cocoa butter it contains. Liq- ceptable to the broadest range of cocoa
uor may be pressed to extract the cocoa processors and chocolate manufacturers.
butter, which is then used to ‘boost’ the •Cocoa mass, butter and powder have
chocolate manufacturing process further added value and are therefore more special-
downstream. ised products. As such they have a narrower
The residue is called cocoa cake, which spectrum of potential purchasers who are
is ground into cocoa powder. Alternatively more discerning in product character and
the liquor may be used directly at the start quality.
of chocolate manufacture. •Cocoa butter is easier to transport, store
Liquor destined for hydraulic pressing and and handle when in cool temperate climates,
removal of cocoa butter must be refined where there is no danger of ambient tem-
Ripe cocoa pod but there's a long way to (ground) to a very small particle size. It is perature approaching its melting point.
go to chocolate. Picture courtesy Omex
Vol. 39 No. 8 15
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