Steeping & Mashing - What is the
difference??Mashing and
steeping are very similar processes at first glance. Both involve soaking
crushed grains in hot water. However, if you look more closely, there are
some sharp contrasts between the two methods.
Mashing is a technique in which malted grains are soaked and
amylase enzymes from the grains convert their starch to fermentable
sugars. Some mashing methods combine malts that are very high in enzymes
with starchy grains lacking enzymes. Other mashing methods only use malted
grains. Mashing methods using adjuncts, such as rice or corn, work because
enzymes from malt are able to move freely about in the mash once the malt
has been crushed and wetted. The amylase enzymes cannot differentiate
starch from malt or rice, and they go about their merry way breaking down
(hydrolyzing) starch into fermentable sugars.
The key to mashing is that the starch
is broken down into fermentable sugars and special attention is given to
controlling the mash environment — I’ll get to that later.
Steeping, is a method used to extract colors and flavors from
certain types of specialty grains. Although the grains are soaked in
hot water, the idea is not to have enzymes acting upon starch. Rather,
steeping merely extracts compounds contained in the malt. The types of
specialty malts ideal for steeping already have the starch converted to
sugars during the malting process. These include the family of crystal or
caramel malts — grain or malt that is roasted to such a high level that
the starch molecules have been modified by heat to the point where malt
enzymes don’t do much to them. Roasted grains and malts include chocolate
and black malt, roasted wheat, roasted wheat malt, roasted rye and roasted
barley. Special malts such as Munich malts, pale wheat malt, pale rye malt
and flaked cereal grains like barley, oats, corn and rice are not
well-suited for steeping because these ingredients all contain a lot of
starch.
The key differences in the actual
processes of steeping and mashing lie mainly in the thickness,
temperature, duration and method used to separate the grain from the
liquid. Mash thickness, or the ratio of malt to water, is important in
mashing because enzymes are affected by the concentration of starch. If
it’s too high, the amylase enzymes lack the water needed to hydrolyze
starch (hydrolysis is a term used to refer to breaking chemical bonds by
the addition of water). If the mash is too thin, the enzymes are less
heat-stable and are more susceptible to denaturation (enzyme destruction).
Most mashes use between one and two quarts of water per pound of malt (~2
to 4 liters/kg). When it comes to steeping, thin is good and it is common
to use ratios as high as six quarts per pound (~12 liters/kg). The thin
steep not only improves the efficiency of steeping, it is also convenient
since the steep water is usually used to dissolve malt extracts after the
steeped grains are removed.
When it comes to mashing, the most
critical variable to control is temperature. Different enzymes have peak
activities at different temperatures, and some enzymes denature at just a
few degrees higher than their activity peak. Brewers have named the
various mash temperature rests for enzymes or their substrates because of
this critical connection. We have the acid or phosphatase rest, protein
rest, beta-glucanase rest, beta-amylase or fermentability rest, the
alpha-amylase or conversion rest and the mash-off step. Few brewers
include all of these temperature rests in their mash profiles, but mash
temperature is always associated with enzymatic activity. These terms are
moot when it comes to steeping. This is not to say that temperature is not
an important consideration when steeping. Most agree that grain-steeping
temperatures should be kept below about 170 °F (~77 °C) to avoid the
extraction of astringent tannins from the malt husk.
Enzymatic reactions take time and most
mashes last at least 60 minutes. Steeping does not require such a long
time because the only thing happening is the dissolution of the malt
solids. Fifteen minutes is more than enough time for steeping. The final
step is separating the grains from the liquid.
Most steepers use a nylon bag that
is easily removed from the steep like a tea bag. Depending on the amount
of grain steeped and the amount of water used, the bag is rinsed with hot
water. Mashing requires the more involved method of separating the wort
from the grains. This process is called lautering. Wort is separated from
the solids in some sort of straining device — for example, a lauter tun —
and is thoroughly rinsed with hot sparge water to extract as much wort as
possible. This step is required in mashing because of the mash thickness.
If the sparging were not used the specific gravity of the wort would be
around 1.080, as compared to sparged gravities ranging from 1.040 and
higher.
MASHING
At the single malt distillery, the barley malt is ground through a mill to
create a coarse grist which passes into a vessel called a mash tun. Three
separate charges of hot water are thoroughly mixed with the
ground malt in the mash tun, a sight akin to an industrial-sized pot of
porridge. The enzymes, which are present in the grinded malt, begin their work, converting the barley’s
soluble starch into a sugary liquid known as wort.
The process of transforming starch into
fermentable sugars is called Mashing.
The Process
Grain content, Malting,
Grinding,
Mashing, Filtering,
Fermenting,
Distilling,
Ageing.
