Grinding

Why grind the malt?

First we need to understand a little bit about the composition of a malt grain to know why grinding is necessary.

The malt grain has a very resistant bark formed from cellulose (the same material that forms the bark of trees). This rigid husk served first to protect the barley seeds, before they went through the malting process.

After the barley seeds are malted, this bark that protected the seeds still remains, now serving as an "armor" for the barley malt grains.

The moment the barley seeds turn into malt grains, they contain all the ingredients necessary for the brewer to produce the brewing wort. However, this interior is still protected by the bark.

What is so precious about the malt grain are, in particular: starch (located inside a part called the endosperm) and enzymes (mainly β-amylases and α-amylases).

It is worth mentioning that this starch from the endosperm is very compacted, to the point of being massive and solid.

The only way to access this content to make beer is to "destroy" the husks of the grains and exposing the endosperm (starch) by grinding.

Once this is done, the grain is ready to perform its primary function of breaking sugar chains with its enzymes.

Although the grinding is a process that sometimes passes by, it is actually very important and has a lot of science involved.

Homebrewing is an art that allows for as much, or little, DIY craftiness as you like. Everything from the recipes you choose to the grains that form your mash can be customized. And whether you’re all-grain brewing or extract brewing, you can fine-tune your perfect beer by crushing malts at home.

But while crushing malts is a little more complicated than “Hulk Smash!”, it’s easier than you might think.

With the right tools and techniques, you can safely move beyond plain old crushed malted barley, introducing specialty grains to your brew and improving beer yield.

Bark x endosperm

The big secret of grinding is: the peel and the endosperm require different grinding goals.

For all-grain brewing, the crush matters because it affects how well the starches, sugars, and enzymes present in the grain will be exposed to water during mashing. The mash activates enzymes in the grain and converts starches into the sugars that become alcohol during fermentation.

The malt peel should be ground as little as possible!

If they are too much ground, the peels can impair the color and flavor of the beer, since they have many bitter substances, proteins (which will “soil” the beer) and polyphenols, which cause astringency (same dry feeling in the mouth as when eating cashew).

In addition, the skins are essential to form the pie, which will serve as a filter to clean the beer in the clarification stage; if the shells are too thin, the pie will “clog” and prolong this process a lot.

In addition, thin shells can cause clogging in the mashing system, causing a lot of problems. The ideal then are peels as integral as possible.

On the other hand, the endosperm (starch) must be ground to almost a powder!

The more the starch is crushed, the better the contact, performance, efficiency and speed of the enzymes (β-amylases and α-amylases) in converting the starch into fermentable sugars during mashing, which also decreases the time of this process and increases its yield .

The ideal is that the starch is crushed enough, to facilitate the service of the enzymes.

A perfect grind would be one that:

- All grains are ground;
- The entire endosperm is extracted from the shell;
- Shells are kept intact;
- Endosperm undergo a fine grind, without reaching powder.

According to what has been said, it is possible to opt for a fine grind, which allows obtaining a greater amount of fermentable sugars, greater attenuation, a greater amount of alcohol and greater yield, or it is possible to opt for a coarse grind, which provides better filtration (less filtration time) and less extraction of substances from the shell, albeit with low yield.

In reality, the ideal is to find a balance in the grind, neither too fine nor too thick. This adjustment will depend on the type of grinder used, the mesh of the "false bottom" or a BIAB used in the mash and, mainly, on practical experience.

The most common grinding options for brewers at home are:

1. Using a disc grinder

This is the most affordable grinder for those who are starting to produce beer. This grinder is designed for manual grinding at the factory using a crank, which can rob you of a few hours of manual labor, but there are versions with a coupled electric motor.

Its operation consists of an endless screw that pushes the grains, as the crank is turned, in the direction of two discs that rub the malt promoting its grinding.

This grinder does not promote homogeneous grinding (breaks most grains), it is difficult to calibrate and clean.

2. Use roller grinder

This grinder consists of two (or 3) rollers that crush (do not crush like the discs) the malt when it passes between them.

It has the great advantage of allowing a very accurate calibration (in the order of millimeters), promotes homogeneous grinding, is easy to clean and performs the grinding quickly, since it can be used with the aid of a drill (or manual).

On the other hand, it has a high price.

3. Grind in the brewshop

It is very practical, sometimes I even got this service for free. However, it does not allow you to have a small stock of malt at home and you are “held hostage” by the store to grind your malt, especially during non-business hours.

In addition, there is a risk that the grinding is not suitable for your needs, since the grinding calibration in stores is generally not adjusted.

Fundamental grinding tips

The first useful tip is when grinding, harvesting and observing some ground portions with different settings of the grinder to choose the best grinding degree. A good grind can be the dividing line between a very well made beer and a very hard mash.

As for the second, you need to have an essential care is that from the moment the malt is ground, it should be used as soon as possible (up to 24h).

Remember, ground malt has lost its natural protection (bark) and is subject to rapid loss of quality and also to the attack of molds that can even produce toxins that are harmful to health.

In extreme cases, store ground malt in the refrigerator, preferable in vacuum bags and use it as soon as possible.

Roller Grinder

Disc Grinder

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