Ask Mr. Wizard

Storing Grains


Ray Snyder - Kelowna, British Columbia asks,

I have a number of different types of grain stored in clear plastic containers that I keep on a shelf in my garage where I brew. The containers are not in direct sunlight, but sun does come into the garage through windows. The garage Temperature ranges from about 39-104 °F (4-40 °C) depending on the season. Am I OK storing grains in this kind of environment, or is there something else that you would recommend?


This is a good question, Ray. The most important thing to prevent when storing malt is an increase in the moisture content. When malt is kilned, the moisture content is normally reduced to less than 5%. Since most parts of the world are not nearly this dry, it is important to prevent moisture pick-up over time. The best way to accomplish this important goal is by storing your malt in airtight containers. It sounds like you are doing that.

Storage temperature is a subject that is not as absolute. High temperature accelerates the effects of aging on all ingredients, but quantifying this with malt storage is not something found in the literature. In fact, none of my brewing textbooks make any mention of malt storage temperature.

The fact of the matter is that breweries and maltsters store malt in malt silos located outdoors. Although high-volume breweries do not store malt for a very long time period due to their high production, many smaller breweries store grain for months in outdoor silos while they slowly consume their inventory. Empirically, one could argue that storage temperature is probably not a major concern in most areas, otherwise storage conditions would probably be different than the use of outdoor silos. Even when malt is stored in bags, the bags are usually stored in closed warehouses that become very warm in the summer.

Historically, pests have been a real problem for grain storage facilities. Pests include birds, rodents and insects. All of these creatures could cause problems in a garage environment, especially if malt is stored in bags that have been opened and closed by rolling the open end. Your plastic storage totes should be a suitable solution to prevent pest problems.

The containers do not prevent light from entering. I have not read, heard or had any first-hand experiences to lead me to believe that light presents problems for malt storage. But then again, most breweries store malt in silos and/or bags and these containers do not allow light to enter. To be on the safe side, you may want to consider placing your containers in a box. But if you are not noticing changes with the aroma and flavor of your malt over time in the beers you brew with stored malt, you have no real issues to associate with malt storage and therefore do not have a problem to solve. In other words, don’t worry!


Response by Ashton Lewis.