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​Sensory Analysis 14. Hot Steep Malt Sensory Evaluation Method​​

​​Hot steep for malt sensory evaluation is a simple, easy, consistent method to extract and evaluate flavors, aromas, mouthfeel, and colors from malt that could translate into full brews of beer. The basic steps are to mill malt, steep it in hot water, filter out solids, and evaluate the liquid with sensory. This method is designed to be repeatable and accomplished with very basic equipment. This method is often used by brewers and maltsters for comparing malts when selecting brewing raw materials for recipes and checking malt sensory quality throughout storage, among other uses.

There are no chemical hazards associated with this method, however the method results in malt dust formation and can be irritating if inhaled. Barley malts contain gluten which is considered a food allergen in sensitive individuals by the U.S. Food and Drug Administration (FDA). Care should be taken to prevent malt dust inhalation and malt tea ingestion by gluten sensitive individuals. Additionally, do not allow hot steeps to sit more than four hours before tasting. Microbial growth may begin and can create potential food safety hazards.

​​This method was originally developed by Cassie Liscomb of Briess Malt & Ingredients Co. in 2015 and was validated and adopted as an Official Method of Analysis by the American Society of Brewing Chemists in 2016. The method was developed to standardize the way in which malts are evaluated by brewers and maltsters.

Hot steep evaluation for malt is simply an extraction of flavors and colors of milled malt with hot water, much like a tea. The temperature of 65℃ and the timeframe of 15 minutes allows for the maximum extraction without adding additional bitterness that higher temperatures would bring. Longer time frames are not needed, as enzymatic activity is not of concern in this test. Recirculating the first 100mL back through the initial grain bed serves as a clarification step of the wort so that color can be better assessed. Because the preparation of the malt hot steep is intrinsically different from a brewer’s mash, the results will not be a one to one translation of beer flavor.

Epquipment & Reagents

• All equipment and reagent needs can be purchased through vendors such as Amazon or at your local grocery store.

• Depending on the number of samples anticipated, multiple units of equipment may need to be purchased (i.e., beaker, funnel, thermos).
• Although a blade grinder can be used, it is more consistent to use a burr grinder with an adjustable gap space. Although slightly pricier, a burr grinder will offer greater milling consistency for malt-to-malt evaluation.
• A coffee filter is an alternative option to the filter papers described in the method. The filtration rate will be significantly slower, but the cost savings may justify the added time. Trial several filter types, find one that works best, and stay consistent with the filter used.
• Be mindful when purchasing a water kettle and ensure it includes temperature control. Many have preset temperature programs and will not allow manual temperature setting.
• Use deionized, distilled, or the water used for brewing for malt steep extractions.

Set Up

• It is recommended to mill and set up all samples prior to adding water to the first sample. Treating all samples as consistently as possible is ideal.
• If grinding different malts, start with the lowest colored malt and work your way up to the highest colored malt when grinding to prevent color and flavor carryover.
• Push the filter down as far as possible into the funnel before wetting the filter with reagent water to help maximize filtration speed.
• Ample water may be used to pre-wet your filter paper. Be sure to remove excess water from the collection beaker before beginning wort filtration.
• Water can be heated to slightly over 65℃ (66-67℃) to make up for temperature loss during transfer.

Extractions

• Once practiced, typical time to mill, steep and filter samples is about an hour depending on filter type. Allow for at least an hour preparation time before having samples ready to taste, an important factor if scheduling people for a sensory evaluation.
• Be aware of timing when setting up multiple samples. When starting the timer for 15 minutes on the first sample in the thermos, be cognizant of how long it takes between the next sample to be able to properly space the pouring of the mash liquids into the filters so each sample sits for the same amount of time.
• Pouring mash liquid into filters as fast as possible creates a grain bed better capable of filtering and clarifying the liquid.
• Try multiple or different inclusion rates for specialty or dark malts if bitterness or masking of flavor is a concern. An inclusion rate that is the same as a brewing recipe inclusion rate can also be helpful.
• Do not allow hot steeps to sit more than four hours before tasting. Microbial growth may begin and can create potential food safety hazards while affecting sensory results.

​​​A Big Thank You To...

​Janelle Harmon, Tiffany Pitra, Libby Stahl, Hannah Turner, and Katie Fromuth.