About Malt – What Is Malting? Malt in Brewing Explained
Malt is an essential ingredient for beer brewing because it contains sugars that yeast converts to alcohol. But have you ever wondered how it came to be?
Malting is the process of converting grains into malt. It consists of three stages: steeping, germination, and kilning. These steps are carefully designed and implemented to activate enzymes, prevent excessive starch degradation, and develop the best malt flavors and quality.
Malting is a crucial step that precedes the other phases of beer brewing homebrewers are more familiar with. This article will guide you through every delicate step and help you better appreciate your malts.
What Is the Malting Process?
Many beer-making guides immediately start with the preparation of materials and mashing.
Even my comprehensive article, How To Make Beer at Home (Easy and Basic Step-by-Step), carefully discusses the journey from malt to beer but does not include grain to malt. The reason is that malt comes ready for use.
But to really understand the essence of beer-making, you must study it from scratch, which is the grain. But to turn grain into a usable product for brewing, you need to understand how malting works.
Malting is the conversion process that turns grain into malt, which is later turned into liquid wort and beer. But the process involves much more than that.
So, let’s get into the details.
Three Key Stages of the Malting Process
To understand how intricate malting is, I will walk you through the three critical stages of this process.
Each stage requires specific materials and conditions that help it achieve particular objectives. Overall, they lead to a common goal – making the best malt.
The first malting stage is steeping, wherein cleaned grain is submerged in water to increase its moisture content and incorporate air. The absorption of water into the grain induces it to begin germination.
But before malting, there are four essential pre-steps:
- Quality check. Grains received from farmers are carefully assessed based on moisture, nitrogen content, foreign matter, fungal presence, water sensitivity, and germination capacity. Those that do not pass the test cannot proceed.
- Drying. Grain received from farmers is carefully dried to allow optimal germination later. Doing so also allows extended storage before actual malting.
- Cleaning. Foreign materials, like stones, straw, and dust, must be removed before malting. Thus, grains are thoroughly cleaned using magnets, separators, de-stoners, and sieving.
- Storage. If the cleaned grain isn’t steeped right away, it must be stored properly. Silos are often used, and proper temperatures are maintained.
The malting process is done by batch. Thus, when I say grains are steeped, I mean hundreds of tons of grains are immersed in water.
Also, this stage isn’t done in one go. The grains are immersed 2 to 4 times in temperature-controlled water and then air-rested between immersions.
The immersion allows water to penetrate the grains. Meanwhile, air-resting makes sure such water is evenly distributed throughout the seed.
After 1 to 2 days, steeping is complete with the following results:
- Increased grain moisture to just below 42 – 47%
- Grains are evenly hydrated
- High chit count
After the grains have been steeped, they are ready for germination.
In biology, germination is the sprouting of seeds. In beer brewing, you should also let the grains sprout at this stage and grow just long enough to modify the grain. As a result, the following occur:
- Enzyme production
- Cell wall degradation
- Solubilization of stored nitrogen and proteins
If the germination process continues, you risk breaking down starch, which you’ll need for mashing and the rest of the beer brewing process.
Therefore, this stage is done within 3 to 5 or 6 days only. During this time, shoots will grow, and the grains will produce and collect the following enzymes:
|Limit Dextrinase||Helps break down amylopectin, a starch component|
|Beta-Amylase||Cleaves a maltose|
|Alpha-Amylase||Cleaves a glucose|
|Alpha-Glucosidase/Maltase||Cleaves a glucoseDivides maltose into glucose units|
Ideally, you want enzymes that break down the starch into maltose, a two-unit sugar made of glucose. It’s the primary sugar in wort; so, you need more beta-amylase to produce much of it.
You also want less alpha-glucosidase or maltase as it counters the beta-amylase action. To learn more about maltose, you can read this writeup: Maltose? The Unrivaled Guide to Understanding Maltose.
Meanwhile, other enzymes that may be produced during germination are:
The end product of this stage is called green malt.
As I’ve stated, germination should only be allowed to proceed for a short time—around 3 to 5 days, which you’ll do through kilning.
Kilning is when you remove water from the green malt using a kiln, a heated enclosure like an oven. It drops the moisture level from around 40% to 4-5% within a day.
Besides reducing moisture, it also does the following:
- Stop growth
- Prevent further starch modification
- Prepare the grain for storage and transport
- Preserve enzymes
- Develop color, aroma, and flavor
Kilning is actually divided into three phases:
- Free-drying. There is a rapid reduction in moisture level in this phase.
- Intermediate. The temperature increases slowly to remove more moisture but prevent overheating.
- Curing. Moisture level finally drops to below 4% while air temperatures are increased.
Conditions, like temperature, are carefully controlled during kilning. A slight misstep could damage the malt, like kill enzymes or form unwanted compounds, such as dimethyl sulfide.
Adjusting conditions also allows you to achieve certain types of malt products. These are the types of malts you may produce:
- Roasted barley
- Roasted wheat
- Light crystal malt
- Dark crystal malt
- Roasted chocolate malt
- Roasted black malt
- Amber malt
These malt types vary based on color, flavor, texture, and storage. For instance, light crystal malt, amber malt, and caramalt are light brown colored, while the rest feature dark shades.
Knowing the different malt types is important because they lead to certain kinds of beer. For instance, lager uses light-colored malts while ales use darker ones.
If you want sweet homebrew, you should use crystal malts or caramalt. To know more about these malt types and sweet brews, read my guide on the types of malts that make your homebrew beer sweet.
Meanwhile, you can also check out my comprehensive guide about the different types of beer. You’ll be surprised by the extensive variety! I’ve also included a list of the 10 most popular beer brands in the world to help you find the perfect beverage for your taste.
Although kilning is often considered the end of the malting process, there are a few post-processing steps before the malt is ready for use or purchase.
One such step is deculming. During this stage, the culms or rootlets of malt are removed. The removed parts can be recycled as animal feed.
The last post-processing step is malt cleaning. Machines, like sieves and aspirators, clean homogenous batches of malt about to be sold.
What Do You Need for Malting?
Malting was traditionally done in large malt houses because space was essential to process large grain batches. However, it is now automated to make micro-scale malting possible.
So, if you’re curious and want to malt your own grains, this overview of malting necessities is an excellent place to start!
There are many types of grain you can use to make malt. The most popular among them is barley, but you can see how they compare to each other based on the table below.
|Grain/Cereal Type||Starch content (%)||Protein Content (%)|
|Barley||50 – 60||8 – 20|
|Wheat||65 – 70||9 – 20|
|Sorghum||65 – 75||6 – 15|
|Rice||75 – 87||6 – 10|
|Corn||75 – 80||6 – 10|
Although barley contains the least amount of starch, it is a preferred option. That’s because it has a husk, which makes the process easier. Its starch-to-protein ratio is also relatively high and favorable.
It’s crucial to choose your grain carefully. The flavors and ease of the malting process primarily ride on that decision.
Instead of malt houses, malting systems are now more popular. The exact equipment depends on the type of the system, and it determines the capacity.
Although I’ve mentioned most malting companies work with hundred-ton batches, processing a few kilograms (or grams) is possible if you have the machinery.
Traditional Floor Malting (Malt House)
A few centuries ago, malt houses (or maltings) were more prevalent, especially in villages in the United Kingdom. They were necessary for meeting local demands—pubs and home brewers (like you!).
These malt houses were large because floor malting required a lot of space.
In this type of malting, grains are spread on the floor during germination. A rake is used to frequently turn the grains for more consistent growth. After germination, the grains are moved into a kiln.
Over the years, most malt houses have been phased out or renovated to suit mechanized production. But there are a few still functioning, mainly to support the production of traditional beers.
Saladin Malting System
The Saladin malting system is often used for large-scale production or processing. It was named after the Saladin box inventor Charles Saladin.
It became a popular replacement for floor malting, where germinating grains were prone to tangling. The Saladin box allows the grains to be turned two or three times a day with little effort and more efficiency.
Nowadays, though, only a few companies use the Saladin system. Most have resorted to buying ready malt, produced by companies that often used drum malting technology.
The drum malting process simplifies and automates the malting process, making it popular among companies. You only need two pieces of equipment for the three key stages:
- Static steeping tank to steep the grains.
- Germination/kilning drum where both phases occur in one large drum.
Some companies may modify the drum malting system and come up with unique designs that achieve optimal performance. For instance, the Skagit Valley Malting does not allow its steeping grains to remain still.
Instead, it uses a rotating vessel to induce even germination with the least amount of water. It also prevents clumping, promotes gas release, forces aeration, and controls temperature.
Small-Scale Malting Systems
There are also small-scale operations most suited to specialty production or R&D operations. For instance, Montana State University can malt at three scales or capacity types:
- Milli malting. Up to 8 kg (17.637 lbs) of barley.
- Micro malting. Up to 120 grams (0.264555 lbs) of barley, primarily for research purposes.
- Pico malting. Up to 5.6 grams (0.0123459 lbs) of barley. Like micro malting, this system is usually used for research.
However, you don’t have to rely on universities to process your small batches of malt. Some companies sell small-scale malting systems that don’t take up a lot of space.
For instance, the IPEC MiniMalt system is designed to handle 100-500 lb (50-225 kg) of barley. It’s an all-in-one system. So, everything is done in one place, from steeping to germination.
Other Uses of Malting
The malting process is especially crucial in our field – homebrewing – because without it, how would we even start making our beloved brews?
But it’s not just in beer-brewing that malting is essential. It ‘s also helpful for distillation, which is used to make spirits (if you’re interested, I have a few articles on making spirits, like this How To Make Vodka – The Ultimate Guide).
Besides making drinks, malting is also valuable for food production, and an example of that is malted bread made from white and wholemeal flour, malt powder, and malted grains. By incorporating malted products, the baked bread gets a gorgeous golden color and unique sweet aftertaste.
Malting is a process that precedes all other stages of beer brewing. It’s how grain is converted into malt, the starter ingredient in many home brewing activities.
There are three stages to malting: steeping, germination, and kilning. The first step induces germination, the second step encourages enzyme production, and the last step cuts off germination and makes the product stable for storage and transport.