We constantly engage in conversations with industry professionals to learn about the challenges they face and the topics under discussion.
Our goal is to write articles that address these issues and provide you with ideas on how to tackle them.
Today, we want to discuss grist and its role in the early stages of the brewing process.
Grist mills come in different sizes and are equipped with rollers. The crucial factor here is the distance between these rollers, as it directly affects the fineness of the grist. This, in turn, determines the efficiency and speed of extracting wort (malt sugars) from the raw materials.
It’s pretty important stuff!
We were eager to understand the nuances of the crush and its impact on efficiencies, flavors, and clarity.
ACE 2000L 4-vessel brewhouse equipment
The grist mill – how many rollers should you have?
This is a good question, and the answer depends on the type of beer you are brewing.
A two-roller mill is the most basic and affordable option, but there is a higher chance of smaller grains slipping through uncracked. It also offers less control in finding the right balance between fine grits and whole grains.
With a four-roller grist mill, you have two points of control over the crush parameters, providing greater consistency and precision.
The first roller is set slightly wider, while the second roller is finer, allowing you to capture all the smaller grains and exercise tighter control over particle size composition.
The grist acts as a natural filter for the wort during straining. Different sizes of grist are necessary to ensure efficient extraction of sugars. The more sugar you extract, the better, as it means less malt is required to achieve your desired alcohol by volume (ABV), thus increasing efficiency.
In simple terms, improved extract yield equals more liters of beer!
How do you determine the optimal distance between the rollers?
The goal is to find the largest possible gap that prevents whole grains from passing through.
Ultimately, the resulting particle size is more important than the mill gap. The perfect grind can only be achieved through experience and possibly a few slow lauters.
In some breweries, the optimal gap may allow some whole grains to pass through, which can lead to smoother runoff and fewer complications during the brewing process.
How can you test the gap length?
This can be a bit tricky.
A feeler gauge or high-precision calipers can give you a rough estimate. However, the resulting particle size is more crucial than a specific measurement.
The feeler gauge provides a starting point, and then the grist sieve helps the brewer fine-tune it for perfection.
How can you test grist coarseness using a grist sieve?
The best approach is to use a series of pans with different screen sizes to assess the proportion of large and small grit particles, all the way down to fine flour.
You are looking for a balance between fineness and lautering ability.
What about pre-milled grist? Is it a viable option?
There are pros and cons to using pre-milled grist.
While pre-milled grist is seen in other countries and can benefit smaller brewpubs by reducing dust, mess, space, and capital costs, it also means relying on the vendor’s mill gap setting, which may not align with your brewing system. If you have your own mill, you can adjust the gap to suit your specific needs.
Savings achieved by optimizing the crush
There are significant savings to be gained from ensuring a proper crush.
Not only does it save money, but it also improves lautering efficiency, saving time for brewers and preventing issues like stuck mashes and the need to refloat the mash bed.
Quality is another factor, with improved runoff resulting in fewer solids ending up in the kettle and a less astringent, lower polyphenol runoff.