Written by BRETT STEIGERWALDT
The TRIAL PROCESS and PRACTICAL APPLICATIONS The history and future use of bacteria in rum fermentations
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elcome to the third article in my four-part series on the rum yeast/ bacteria selection process and how to successfully trial them at your Read Part One facility. The first article (Winter 2024) briefly covered the history and use of bacteria in rum fermentations. The second article (Summer 2024) focused on the nine-step rum production process that must be considered before embarking on a yeast trial and subsequent product development. This article will describe the Read Part Two triplicate trial process (including trial logistics and planning techniques), recommend specific testing that will provide the most actionable information, and demonstrate how this process would be approached at Lyon Rum using common distilling equipment. Remember, just because you don’t have a modern laboratory doesn’t mean that you can’t explore novel fermentation techniques!
PART THREE
Setting up our experimental design
Now that we know our candidates and pitch rates, we need to set up our experimental design before we can proceed further. For those unfamiliar, an experimental design is how we structure our trials so that we clearly know our intentions, understand the potential outcomes, and can better set up process flow to ensure smooth implementation. I prefer to do this visually (Figure 1), as it dramatically simplifies our at-a-glance understanding, gives us a check to ensure that we’re on track, and makes purchasing/allocating equipment significantly easier. As stated above, we’re You may be asking yourself, “Why do I Let’s recap performing each process step in triplicate — need to perform triplicate trials for each canPlease refer to Table 4 of my previous artiwhich means three fermentations (i.e., Trial didate?” The reason is simple: This is the mincle. These are the 17 yeasts and bacteria that 1A, 1B, 1C), three stripping runs, and three imum number of trials that can be performed I chose for my trials (this has since been exspirit runs where all products will be aggregatthat allow you to make comparisons within panded for several reasons, which I’ll discuss ed (remaining low wines from each trial segeach trial, between trials, and to ensure that in part four). For this article, I’ve paired these ment and their heads, hearts, and tails). These the data you’re generating is accurate. Just bedown to nine candidates (Table 1), updatnon-hearts aggregated products will then alcause a fermentation is performed a certain ed some of the yeast nutrients, and deterlow us to perform one production-style spirit way doesn’t mean it will always do this, and mined our pitch rates according to my experun at a chosen low wines, heads, and tails three trials allow us to be reasonably certain rience and via continued conversations with ratio. Then, we can compare the aggregated of candidate performance. suppliers. hearts to the production-style hearts and decide our next production steps: scale up, TABLE 1. List of fermentation trials showing their composition and dosage rates for yeast, nutrient, and bacteria. modify fermentation Note: the three dashes (- - -) indicate that no bacteria will be used in these fermentations. ratio, modify stripping Dosage (g/L) run and/or spirit run Trial Composition Yeast Nutrient Bacteria cut points, or some 1 Pinnacle S Yeast + OptiStill Rum Nutrient 0.5 1 --combination of these 2 FSI-048 + FermLife 0.26 0.26 --actions. 3 SafSpirit™ M-1 + Springferm™ Complete/Equilibre 0.5 1.75 --Are you lost? If so, 4 SafSpirit™ M-1 + Springferm™ Complete/Equilibre + SafSour LP 652™ 0.5 1.75 0.1 no worries, it’s a lot to 5 DistilaMax® CN + DistilaVite® GN 0.4 0.26 --keep track of and we’re 6 DistilaMax® CN + DistilaVite® GN + DistilaBact® LP 0.4 0.26 0.1 still in the planning 7 DistilaMax® CN + DistilaVite® GN + Lalvin VP41™ 0.4 0.26 0.01 stages. This is why our 8 WLP028 Edinburgh Ale Yeast + WLN2000 FANMax Bio™ Yeast Nutrient 8 pouches 0.26 --experimental design is so important! 9 D022 Tropical Rum + MicroVit Distillers Micro Nutrients 0.5 0.35 --70
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