These two terms, malting and mashing . . . what do they mean to you? The malting process is a fairly broad and generic term given to processing raw grains just as mashing can have a fairly broad definition as well. So let’s delve in to investigate why these two terms can be so fluid and to use this understanding to your benefit as a brewer.
The malting process begins with the raw seeds of a cereal grain, sometimes referred to as berries of the grain. For brewing, the grain is typically barley but wheat, rye, and oats are commonly used as well. The malting process starts with steeping in water. This is simply to hydrate the seed. Next up, in the same way a gardener might start the seeds for the summer’s garden, the maltster germinates the seeds in a warm and humid place allowing them to sprout. The germination step is vital for brewers since it gets a few key biological processes into gear in the grain including the formation of the enzymes that all-grain brewers are going to need during the mashing process. Without this key germination step, brewers would be unable to process all the starch that the grain contains . . . no starch conversion, then no sugar . . . no sugar, then no fermentation . . . no fermentation, then no alcohol.
All malted grain goes through this germination step, but once that happens the processes diverge, leading down multiple paths to end up with the cornucopia of malted grains we know. To start, how long the grain is allowed to sprout changes the proteins, enzymes, and starches. Next the malts will either be toasted/kilned, drum-roasted, or stewed. If they head off to be toasted, there are a few directions for them to go. They could be lightly toasted to halt those enzymes and create base malts. If they are toasted further, then the enzymes are destroyed, making it a specialty malt such as biscuit malt that requires base malts in the mash to work on the starch. Malts can also get heavily toasted in large rotating drums to become roasted malt. And just like coffee roasting, there is not one set way to toast the grains. Maltsters utilize unique roasting profiles with different times and temperatures to obtain the characteristics of the many specialty malts like pale chocolate, chocolate, and black.
The maltster has set the stage for the brewer. Now it’s time for the brewer to set the stage for the yeast.
Alternatively, grains could be stewed, which will land them in the class of grains we know as caramel/crystal malts. Stewing implies that these grains will be treated similarly to grains that are being mashed, but without the crush. In that case, the starch in the grain is converted to sugar, but instead of this happening in the mash, it happens inside the grain. Once the stewing is done and the starch is converted to sugar, the grain is then toasted to varying levels depending on what degree crystal the maltster is after. Again, different temperature and timing profiles apply. The fact that it is sugar in the malt and not starch is quite significant for the brewer as these crystal-type malts are much different taste-wise compared to toasted grains. The conversion of starches to sugars is also why these grains can be steeped to add flavor and a mix of fermentable and unfermentable carbohydrates.
By the time the brewer purchases their grains, all this has been done. The maltster has set the stage for the brewer. Now it’s time for the brewer to set the stage for the yeast. The sugar profile of the wort, which is just a name for the sugar water produced by a brewer, will be set by the grain selection, the mash temperature profile, and duration of the mash. All this comes together as the enzymes created during the germination stage start to break down the highly complex starch molecules. The target mash temperature allows brewers to favor a specific enzyme, each of which works on the starch granules differently. Cooler and longer duration mashes create drier beer in the end since the enzymes can more finely chop up the starch molecules. Warmer and shorter mashes generally mean fuller-bodied, sweeter beer since the enzymes, figuratively speaking, are going to be randomly hacking at the starch and will produce more unfermentable carbohydrates, a class known as dextrins. And generally the more specialty grains that are added to the mash, the more unfermentable sugars are going to be found in the wort as well.
So what about malt extract? Well, in these products the maltster has completed the process just as they would do for standard malt. But then they actually employ a brewing team to make the brewer’s wort in a huge mash. When the wort has gone through the mash phase, it is then vacuum boiled in order to concentrate the solution while minimizing the chemical reactions that typically happen in a brewer’s boil kettle (like melanoidin and caramelization reactions). Once the wort is reduced down to syrup at about 80% sugar, then you’ve got liquid malt extract. The liquid can be further concentrated by a process known as spray drying, which will produce dried malt extract. Dried malt extract has all the water removed. The beauty of malt extracts are that they are brewer’s wort . . . simply in concentrated form. The problem some folks have is that you lose control over the mash parameters mentioned in the previous paragraph. But with a skilled touch extract brewers can find ways to adjust these as well with things like sugar substitutions to dry the beer out or body building steeping grains to get a more full-bodied beer.