Mashing is the process of activating the various enzymes that are present in the
grains to break down the carbohydrates to sugar molecules of various types. This
process is called saccharification.
It is done by heating the grain with just enough water so as not to dilute the enzymes
to the point that they don’t do their job.
The 2 main enzymes we are concerned with here are Alpha-amylase and Beta-amylase.
Alpha is active in the 140-149 F range while Beta is active in the 149-158 F range.
What do the 2 enzymes do you might ask?
Well many things, the science behind it can fill a book on it’s own and there are
more complex reactions that are desirable when mashing than just conversion of carbohydrates
and starch to sugars that the beer yeast can feed on. There are nutrients that get
created during the mash that also help the yeast and compounds that later affect
beer color, taste, and stability. You can look to the reference section if you want
to get pointed towards some books and online sites for the details.
The main sugar compounds that come from mashing are: Monosaccharides, Disaccharide's,
Trisaccharides and the rest gets lumped into dextrins which are not normally digestible
by brewing yeast but add body and mouth-feel to the beer.
The mash usually continues for 45 to 60 min's ( and longer depending on mash style
) although complete conversion can occur in as little as 15 minutes with today's
highly modified malt. As mentioned before though, there is more going on in the mash
then just breaking down carbs, so mashing for more than 15 min's usually occurs for
production of other elements for the finished beer and depending on what style of
brew one is shooting for.
The mash can be single infusion - set a temperature in the middle of where Alpha
and Beta amylase are active - , Multi rest - stepped through various temp increases
called rests because it is held there for 10 to 30 min's before going on to the next
rest or Decoction - remove part of the mash ( sometimes multiple times ) and bring
to a boil then reintroduce to the main mash. In the end when the brewer is satisfied
things are where they should be, the mash-out is set at around 170 F. This denatures
( de-activates ) the enzymes.
The act of sparging then begins. This is nothing more than the slow trickle of heated
water in the 172 to 176 range onto the grain bed to gently wash the wort out of the
grains and into a boil kettle for the next stage. Too hot and you leach out harsh
tannins and flavors. It should be noted that sparging can take longer than mashing.
If one is doing an single infusion mash, they could be ready to sparge in 20 minutes!
Sparging could take 45 min's to an hour !
The PH of the outbound wort is monitored and when it reaches a certain point, sparging
Setting a temperature and holding it throughout the mash. Most ales are made this
Stepping through multiple temperature ranges and holding them for a bit called a
Removing part of the main mash, heating or boiling and then returning to the whole.
German dopples and such are made this way.