PRACTICAL APPLICATION SERIES — PART 2
Written by Pete Barger and Samantha Harpst
Clean Grain, High Gain Practical Strategies for Ethanol Yield Maximization
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▶ Each load of grain should have a unique lot code identifier. By sepa-
rating each grain delivery with a unique code that follows the grain through all testing and use, you can track it from lot to bottle. It’s extremely important that all grain consumption follows a first-in, firstout approach to minimize storage time — and reduce the chance of moisture or infestation.
y some estimates, distilling has been around since 2000 BCE, and it’s true that the basis of the process has remained inherently the same for millennia: Sugar/Starch Source + Yeast = Alcohol. This ▶ A 1-pound sample from each truck or bag — roughly a quart-size fermentation reaction will stay true until the end of time. But as the plastic bag — should be collected for a visual inspection. Create a industry leans deeper into the science of fermentation, analytics have grain grading document for the team member responsible for unbecome the driving factor for innovation and consistency. We now unloading the grain to fill out. This creates a structured data record for derstand that great products start with a great base derived from grain that lot. The document should include acceptable ranges for foreign quality, consistency, and accurate measurements. In this article, I’ll material, germinating grain, insect damage, and any other grain-speshare practical ways to monitor the quality of both raw materials and cific metric (for example, cracked processes to help maximize ethanol production and fermentation conkernels for corn). The sample sistency in a distillery. st standards should then be sorted with tweee h ig h e th g All fermentations need a raw materiBy maintainin zers by a team member, separating eer produced al source for sugar/starch, the food that b e th , ty li a u q in ra g any grain or foreign material found of yeast consumes to produce ethanol. For to batch h tc a b t n te is in the sample. Once fully sorted, each this piece, I will focus on bourbon producremains cons rs ie tl u o category should be weighed and a fy ti n tion and the methods we currently employ ws you to ide o ll a d n a percent of total weight calculated to at our distillery. Grain is the foundation of r profile. o v a fl t e rg ta determine if the load passes your inthe finished product. By maintaining the from your house specifications. This data collection highest standards of grain quality, the beer also helps your team communicate with local or industrial growers produced remains consistent batch to batch to ensure that quality stays in line with your targets. and allows you to identify outliers from your target flavor profile. Although most large grain elevators or incorporated farmers typically provide a certificate of analysis (COA), running in-house quality tests on all incoming grain helps your team get familiar with the grain and develop specs that every batch must meet. Ideally, these in-house tests should happen before unloading, so you can reject a load if needed — but I know this isn’t realistic for all distilleries, especially smaller ones. Even if you can’t reject a truck, collect data anyway. There’s a wide variety of simple in-house tests and best practices you can run with little or no additional cost to ensure the best raw material quality:
▶ All grains should be segregated in bins at the facility to prevent
cross-contamination. This is especially crucial when the distillery is producing mash bills that use multiple types of grain. By isolating each grain in an individual bin, any problems with that grain can be traced to one bin instead of multiple — saving thousands of dollars if there’s ever a breakout of mold, insects, or another quality issue. A perfect example of this occurred a couple of years ago in North Carolina, when the wheat harvest had a higher-than-normal rate of DON (vomitoxin) due to a wet, humid winter. By isolating wheat in one bin, we were able to mitigate the chances of corn or rye becoming contaminated and uphold our grain’s integrity.
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▶ That same 1-pound sample can be reused for a grain health analysis.
Dicky John® Moisture Testers, or similar instruments, allow for the moisture and test weight of incoming grain to be checked on-site at a rapid rate. This simple test shows the grain’s quality based on test weight and gives you usable data for yield comparisons later. The data should be recorded on the grain grading sheet for that lot.
▶ A small portion of the collected sample should be microwaved for a
sensory analysis. Place the grain in a Glencairn glass, cover it with a small piece of blank paper, and microwave for about 10 seconds. This releases the grain’s aroma, allowing you to detect any off-notes—particularly mustiness—that could carry into the final product. Record any detected aromas on the grain grading sheet for that lot.
The grain is just the beginning. Sanitation is the backbone of flavor profile and efficiency in distilleries because it fights the biggest enemy — bacteria! Bacterial contamination is the largest risk factor for fermentation tanks, both when empty or full. Lactobacillus bacteria (LAB) and acetic acid bacteria (AAB) are the two most common types of bacteria found in the fermentation tanks. Lactobacillus is a common type of bacteria that humans encounter every day in products like yogurt and sourdough bread. Similarly, AAB’s byproduct, acetic acid, is 79