by Blake Sandnes

How to Mill Grain for Brewing

What Is a Brewing Grain Mill?

Image of holding grains of malt in hands.A grain mill is a piece of equipment that is used to crush grain. It takes the whole malted barley, processes the grain through the mill, and deposits crushed barley out the bottom. 

Inside of the mill is a set of rolls with teeth. These cut into the whole grain providing an initial pressure on that barley to separate the husk from the endosperm. After this, the endosperm is milled. It is important that the crush is neither too fine nor too coarse, but rather somewhere in the middle. From there it is ready to go into the mash tun (an insulated brewing vessel with a false bottom) for that first mash process.

Is it Possible to Over-Mill or Under-Mill Grain for Beer?

Contrary to popular belief, it is absolutely possible to over-mill and under-mill barley. The process requires precision grain mill brewing equipment and careful tuning. If the rolls are too close together, and the grain is excessively milled, that will damage the husk. Damage like this prevents the fluffy filter bed desired in a mash. The mash can then fall to the bottom of the tank and create a hard, rock-like blockage.

If the barley is under-milled, there will be too many sugars left in the grist. Brewers want to get as much sugar off that grain as possible. If a grain is undermilled, the endosperm is not exposed to the water in the tun and therefore, an efficient amount of sugars will not be released.That is why a consistent crush is extremely important.

What Is an Ideal Crush for Brewing?

Mashing of milled malt grains for preparing malt. Process of brewing grain of barley. The ideal crush for a brewery is going to vary slightly depending on the beer brewing grain mill being used and the type of beer being brewed. Consistency is the most important factor. Ideally, the husk remains intact as much as possible while still milling the endosperm to a consistent size. This allows brewers to extract as much sugar as possible, and maintain a consistent filter bed. 

Grist analysis is typically performed with a set of sieves to dial in the grind and get the best extract from each grain. The industry standard for the brewing uses three increasingly fine sieves—a 14, 30, and 60 is typical—as well as a pan. An ideal result in an analysis is consistent distribution. Depending on the equipment, that varies from 55-75% in that top sieve, about 20-25% in the middle sieve, and maybe 15-20% in the finest sieve. Finally, it’s recommended keeping that pan under 10%. However, this will all vary depending on the design of the brew house. 

How Long Do Grains Last?

The timeline in which milled grains are good for brewing can vary quite a bit and growers will offer different opinions. Some argue that as soon as the grain is crushed, it starts to deteriorate. On the other hand, different malthouses provide pre-milled grains for breweries, and the lifespan of that grain is roughly three months. On average, the recommendation is to use grain within the week that you crush. 

What Should You Look for in Quality Milling Equipment?

Beer ingredients with various grains illustrating different colors and the beers produced from different mixtures of grains.Whether you are looking for a homebrew grain mill, or something larger and more industrial, there are several items to look for in grain mill brewing equipment. The first is a mill that once set, will not drift. A quality mill is going to be at that perfect setting for the duration of your brew day and beyond. 

The next sign of quality is adjustability. There may be some grains where a different gap is preferable. Malted oats require a bit finer of a crush than wheat. A machine with easy adjustability maximizes efficiency in a grist mill.

Total cost of ownership of that equipment is also a factor. A lower priced brewing grain mill can be enticing, but it could be made overseas. This makes finding spare parts and troubleshooting mechanical issues more difficult, time-consuming, and costly.

How to Find the Right Grain Handling Equipment

With grain handling equipment, there are many different options available, but the best choice depends on a range of factors and preferences. How fast do you want to move material? How gentle do you want to be on the grist? How much space do you have? 

There’s a variety of options and sizings for silos, conveyance equipment, and weighing equipment, but only a grain mill brewing expert can guide you to the right choice. 

When you are ready to speak with an expert, contact the team at RMS Roller-Grinder. We have a deep understanding of the grain mill brewing process and we have dozens of connections in the industry to help lead you to the best choice for your brewery. Contact us today!

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