Shelf-Life Testing… 2 Years in the Making!

We all know that high-quality food and beverages start with high-quality ingredients! On the wing of this, Grouse is excited to announce the completion of our 1st round of extensive shelf-life testing on various products to observe how they change over time, over 2 years of storage! Doing so has allowed us to gain valuable insight and communicate with evidence the best time frame in which to utilize our malts, including any sensory changes you can expect.  

Historically, we gave a blanket statement to use Grouse malt within 18 months of creation. In this shelf-life study, we took our Pale Millet Malt, Goldfinch Millet Malt, Pale Buckwheat Malt, and Chocolate Roasted Millet Malt in both milled and whole grain forms stored in our standard packaging (PPE5, lined bags) in our packaging warehouse. Each product was tested for color, moisture, and sensory each month starting in the spring of 2021. Now, 2 years have come and gone and we’re ready to share this data with you!  


General findings applied to all malt types:  

Moisture levels: Over the first few months after processing, all stored malt moisture increased slightly, likely due to the fact that the packaged bags for this experiment were 4” sewn on 3-4 sides. If the malt were to increase in moisture significantly, flavor would start to degrade more rapidly. Grouse is based in Colorado, which has an arid climate. Brewers located in more humid climates and store malt for an extended period of time should ensure they visually check their bagged malt before use. While our bags are a poly woven PPE with a laminate layer, and are moisture proof, there is some moisture migration that could occur in the sewed ends. 

The durations addressed below are month long approximations and are based on storage in a warehouse with temperatures ranging from 45-80°F depending on the time of year.  

Color Testing: All samples showed slight variation in color, but no samples tested outside the color specifications for the respective product.  

Sensory: All milled samples experienced degradation faster than their whole malt sample equivalents. 



Pale Millet Malt: 

Milled: Passing sensory panels for up to 12 months. 

Whole: Passing sensory panels for up to 18 months. 

Past these periods of time, aroma and flavor leans into heavy dough notes.  


Goldfinch Millet Malt: 

Milled: Passing sensory panels up to 24 months 

Whole: Passing sensory panels up to 24 months. 

At month 16, aromas began to shift to heavier cereal/bran notes and away from the caramel notes. This is tough to judge because most panelists will still pass this as it is not a negative aroma but is not the balance of aromas we expect from fresher samples.  


Pale Buckwheat Malt: 

Milled: Passing sensory panels for up to 18 months. 

Whole: Passing sensory panels for up to 18 months. 

As buckwheat ages, especially past 18 months, the grassy aromas start to take over. Haze starts to slowly increase over time after month 12.  


Chocolate Roasted Millet Malt: 

Milled: Past month 12 sweetness and chocolate aromas begin to diminish. 

Whole: Past month 12 sweetness and chocolate aromas begin to diminish. 

After 12 months the roast begins to lose its freshness but was passing our sensory panels throughout the 24-month period.  


Below is a summary of Grouse’s shelf-life results and our recommendations.  

The recommended shelf-life stability for Pale Millet Malt is 18 months, whether or not it is milled. After the 18-month timeframe, flavor takes on a more pronounced doughy characteristic and aroma characteristics begin to become unbalanced and doughy. 


The recommended shelf-life stability for unmilled Goldfinch Millet Malt is 24 months. Very few defects were noticed over this period. Milled Goldfinch started to show flavor imbalance after 18 months, and muted and unbalanced aroma in the 23rd month. Given that Goldfinch is a high-dried malt, we expect other malts like it, such as our Dark Munich Millet Malt, Red Wing Millet Malt, and Griffin Millet Malt to maintain their sensory characteristics longer than lesser kilned malts, such as Pale Millet Malt, Munich Millet Malt, Vienna Millet Malt, Cara Millet Malt, and Caramel Millet Malt.  


The recommended shelf-life stability for milled and unmilled Pale Buckwheat Malt is 18 months. Aging after 18 months causes a slight haze in the hot steep results and starts to develop grassy aromas. 


The recommended shelf-life stability for milled and unmilled Chocolate Roasted Millet Malt is 12 months. After 12 months, sweetness and chocolate aromas begin to diminish. Loss of freshness begins to set in at 14 months. 


Our findings were consistent with Grouse’s historic recommendations in the whole seed form. However, we encourage our customers purchasing pre-milled malt to use this product within 12 months or less. We look forward to expanding on this initial shelf-life test to include other SKUs such as our Yellow/Blue Corn malt, other high-dried malts, and Pale Oat Malt. Thank you to our quality team for their monitoring of this research. Please contact us at with questions about our product’s shelf-life!