Making The Perfect Grist

We are always chatting to people in the industry, trying to learn about the problems they are facing and the issues being discussed.

We try to write articles that can help with these issues – and give you ideas about how you can do things.

So today, we want to talk about grist – and the process by which it is made, in the early stages of the brewing process.

The mills are made in different sizes and contain rollers. And here’s the important part – the distance between these rollers is directly related to how fine the grist becomes – and this determines the efficiency and speed of the process of extracting wort (malt sugars) from the raw materials.

Pretty important stuff!

We wanted to understand the nuances of the crush and how it can impact efficiencies, flavors, and clarity.

DEGONG 2000L 4-vessel brewhouse equipment

The grist mill – how many rollers should you have?

This is a good question – and it depends on the beer you are brewing.

A two roller mill is your most basic type – and the cheapest price point as there is a stronger chance for smaller grains to slip through uncracked. You also have less control, as it’s more difficult to find the balance between fine grits and whole grains.

With a four roller grist mill, there are two points at which to control the crush parameters. This allows greater consistency and more control over the crush.

The first roller is set a bit wider, while the second is a bit finer, so you can pick up all the smaller grains, allowing tighter control over the composition of the particle size.

The grist acts as a natural filter for the wort to strain through. Different sizes are needed to ensure you get good lautering of the grist to extract sugars. The more sugar you can extract the better – as this means less malt is needed to reach your intended ABV therefore increasing your efficiency.

Basically – improved extract yield = more litres of beer!

How do you determine the optimum distance between the rollers?

You are looking to find the largest possible gap without allowing whole grains through.

Really, the ultimate measure is to  assess the resulting particle size rather than the mill gap. The perfect level of grind can only be found through experience – and likely a few slow lauters.

In some breweries, the optimal gap may actually allow some whole grains through – with the end result being less headaches and actual ease of runoff in the brewery.

How can you test the gap length?

This is where it can get a bit tricky.

A feeler gauge or high precision calipers will get you in the ballpark. However, the resulting particle size is far more important than a number.

The feeler gauge will just give you a starting point – then the grist sieve will help the brewer dial it into perfection.

How can you test grist coarseness? A grist sieve?

The best way is to use a series of pans with specific screen sizes to assess the amount of large and small grits all the way to fine flour.

You are looking for a workable tradeoff between the fineness of the crush and lauterability.

What about pre-milled grist? Is that a thing?

There are pros and cons to using pre-milled grist.

You do see pre milled grist in other countries and for the smaller brewpubs it reduces the dust and mess, while saving on both space and capital outlay.

But ultimately, with pre-milled grist you are at the mercy of the vendor’s mill gap setting which may not suit your particular brewing system.  If you have your own mill, you can set the mill gap the best suits your application.

Savings found in getting the crush right

There are many savings to be found in ensuring a good crush.

There is also the obvious cash saving – but I think the real value lies in the improved lautering, with time saved for frustrated brewers who can avoid stuck mashes and refloating the mash bed.’

There’s also the quality factor, from improved runoff with less solids ending up in the kettle – resulting in a less astringent lower polyphenol runoff.