top of page
  • jerid7

Hydrating Grain Before Milling with Grain Mills

One of the important factors in getting the most gain for your grain is managing the moisture content. Too much moisture in grains can lead to the growth of mold on the grain when it's stored for long periods. Mold will spoil feed grains because the mold itself eats the nutrients, and livestock, like people, don't think moldy grain tastes very good, causing them to reject it. However, it might be even worse if they eat the moldy grain, because many molds produce dangerous toxins.

To avoid mold growth on feed grains, they are often stored dry. However, feeding grain in this condition reduces the efficiency of intake and reduces your average daily gain (ADG) for animals. Hydrating grain is a technique that lets you store the grain relatively dry, while getting the benefits of wet grain when you feed it.

Benefits of Hydrating Grain Before Milling

Dry grain stores well. Wet grain is best for processing and for digestion. The obvious solution is to store the grain dry, then hydrate it before milling. The benefits of this approach include:

  • Little to no risk of moldy grain

  • Long storage life for grains

  • Purchasing flexibility

  • Reduced cost of processing

  • Reduced wear on grain mills

  • Lower dust production

  • Improved digestibility

  • Higher ADG

By storing grains dry, you can reduce or eliminate the risk of mold growth in grains. Molds need a high level of water activity to grow and even higher levels to produce the toxins that affect livestock.

Farm worker sorting through dry grain feed
Farmer sorting through dry grain

If your grain is dry, you can store it for longer. This frees you up to buy grains in larger quantities. Larger quantities can lead to better prices, and it can also give you more flexibility when you buy, helping you find the best prices for your grain.

Hydrated grain is easier to process, so it reduces the cost of processing. Hydrated grain is also softer, so it leads to less wear on your mill’s rollers. And while roller mills already produce less dust than hammer mills, hydrating your grain can reduce the amount of dust produced even further.

The final effects of hydrating grain can benefit your bottom line, helping your operation remain profitable. The hydrated grain is more digestible by your livestock, which can increase your ADG significantly, while reducing your daily grain ration per head. Some studies suggest you might see a 10% improvement or more with hydrated grains.

Hydrating Feed Grain Is Not "Wet Milling"

Before we talk about the different approaches to hydrating grain, it's important to distinguish between hydrating grain and "wet milling." In relation to human and animal food, wet milling is a different process in which grain, especially corn, is soaked or "steeped" in water and various chemicals to soften it and prepare it for separation. The germ and oil are separated, then the bran is washed off. Gluten and starch are separated in a centrifuge, creating a number of distinct corn products, some of which are used in animal feed, but others of which are used in different applications.

However, when brewers talk about "wet milling" or "conditioned milling" they mean a process of introducing water and grain to the mill at the same time. The goal is to increase the water content of the grain husk. This helps the husk to stay intact during milling, which reduces the production of dust and makes it easier for the lautered water (wort) to run off the grain, making the process more efficient.

grain silos in a harvesting field at sunset

Methods For Grain Hydration

Tempering Grain

Tempering is the most straightforward way to hydrate grain before milling. In this technique, grain is passed through an open augur past a wetting station. A controlled amount of water as well as some surfactants or other treatments are added to the grain at the wetting station. Then the grain goes to a tempering silo where it sets for up to 24 hours, allowing the moisture to penetrate the grain.

Then the grain goes to a roller mill.

Steam Flaking Grain

Steam flaking is the most energy-intensive approach to hydrating grain. In this process, grain is first tempered, then passes through a steam chest at around 212 ° F for half an hour to an hour before passing through corrugated rollers for flaking. Most people are familiar with flaked oats, but many different types of grains can be steam flaked.

Steam flaking uses energy in many parts of the process: running the augurs, generating steam, and rolling the grain. It also requires a significant amount of specialized equipment, including a steam chest and a specialized flaking mill.

While steam flaking can increase the efficiency of feed, the high energy costs means it is usually not worth it for most operations. And the increased feed efficiency is usually less than using either high-moisture corn (HMC) or using reconstituted grain.


Reconstitution is a passive process that can achieve an even higher level of moisture content than steam flaking. Because it's passive, it doesn't require as much energy as steam flaking.

The reconstitution process begins with tempering the grain.

Then more water is added to the grain, and the grain is ensiled for at least 14 days. Airtight storage not only keeps moisture from escaping, it ensures the grain absorbs the moisture thoroughly. The grain is then rolled before using it as feed. Reconstituted grain can have a moisture content as high as HMC, up to 32%. It's very easy to process and can significantly increase ADG for pigs and cows. It is very frugal in energy usage. It does, however, require a special airtight silo.

Want to Find the Best Grain Mills for Your Operation?

Early company photo of Automatic Equipment
Serving agricultural professionals since 1925

There are definitely benefits to hydrating your grain, although, admittedly, the options can get a bit confusing. At Automatic Equipment Manufacturing, we've been helping farmers, ranchers, and feedlot operators make complex decisions about grain processing for nearly 100 years.

If you are looking to talk to someone about what grain mill might work best for processing your feed grains, please contact us today.

814 views0 comments

Recent Posts

See All


bottom of page