Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824
Performing Department
Food Science
Non Technical Summary
The practice of production of distilled alcoholic beverages dates back to ancient times and prior to Prohibition there were literally thousands of distillers in the US. Only now, eighty years after the repeal of Prohibition, are small scale, specialty, "artisan" distillers making a comeback. Unlike their large corporate counterparts, these artisan distillers are much closer to the production of the raw materials and are integrated with the vineyards, orchards, and farms that provide their required raw materials. Fifteen years ago in Michigan we had no such artisan producers. Today there are over thirty commercial producers with a number of others contemplating entering the business. The economic potential for artisan distilling is quite high in that this industry provides three sources of finances: value added agricultural products for the producers, job creation, and, unlike most other product categories, a substantial public source of funds through both State and Federal excise taxes and mark-ups.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
1. Screen a series of beverage related yeasts to determine the amounts of fusel alcohols produced. Determine the effects of pH, temperature and sugar source. Any unusual nutritional requirements for the yeast will be deremined.2. Perform economic analysis to determine the effect of possible yeast change on an industrial process.
Project Methods
By objective:Screen a series of beverage related yeasts to determine the amounts of fusel alcohols.1. Pretreatment technology. The pretreatment of raw materials to release sugars for fermentation will be studied for a number of feedstocks including potatoes, grains, molasses, and fruits. The primary focus of the study is the use of processing enzymes for liquefaction (pectinases, cellulases, α-amylases) and saccharification (β-amylases and glucoamylases). A collaboration has been established with Novozymes in Denmark to supply enzymes for the study. The sugar compositions will be monitored using HPLC. Use of standard HPLC techniques allow determination of all simple sugars such as glucose, etc. and allows the determination of the extent of reaction during the pretreatment step.The general approach follows the American style of whiskey production in that grains will be milled to a flour and then exposed to hydrolysis. This approach differs from production of whiskeys that use a lautering technique, i.e., roller milled grain is mashed and the grain is removed before fermentation (lautering). This difference leads to an inverted temperature profile in the mashing stage. The current work heats the mash to 80C, adds the first set of liquefaction enzymes, allows reaction, cools to 50C, adds the second set of saccharification enzymes, allows reaction, and is cooled to fermentation temperature. The lautering process heats and then rests at several temperatures, allowing the native enzymes to react. By the time the temperature of 80C is achieved the naturally occurring enzymes are destroyed. Our approach is far more reproducible and can easily be scaled up. A second feature of our approach is that all cook steps are done at atmospheric pressure, eliminating high pressure cooking that has both cost and safety concerns.Two mashing vessels will be used with volumes of 400L and 6000L. These two vessels allow the study of issues that can arise in the scale-up of the pretreatment process.2. Fermentation technology. Various yeast strains will be tested to determine optimal conditions for fermentation. The strains will be tested for speed and robustness (lack of infection by other organisms). The main objective is to match strains to the raw materials. The extent of fermentation will be monitored using GC, HPLC, and refractometry. HPLC is particularly good for tracking the consumption of sugars, evolution of ethanol, and identification of contamination (e.g. formation of lactic acid by contaminating bacteria).Fermenters are available for the project at the 1L, 30L, 400L, 14,000L and 16,000L scales. Most of the studies will utilize the larger two fermenters. While most studies will use commercially available yeasts, the availability of the seed train will allow yeast strains to be propagated from a slant all the way to production scale. Typical runs with start with mash provided by pretreatment step being inoculated with the desired yeast strain. The fermenters are stirred and jacketed with temperature control.3. Distillation technology. The MSU distillation facility established at 2000 Merritt Road, East Lansing, MI will be used for distillation studies. A nine meter, 17 tray continuous column is available for stripping of mash. Batch pot stills ranging from 10L (with three trays), 145L (with three trays) 165l (with three trays and a two meter packed column), 450L (no trays with a botanical basket), and 800L (with 44 trays) are available for finishing of spirits on the project. Vodka requires more separation that most types of whiskey and brandy, so the large column (44 trays) will be used. The distillation will be monitored using GC with FID detection. Since the finishing runs are completed batch-wise the GC measurements provide for consistent cuts between the different fractions coming off the still in time. 4. Storage conditions. The effect of storage on final product will be studied. Barrel aged spirits will be stored in standard 53 gallon barrels. Reactions that occur during storage (oxidation, esterification, and acetalization) will monitored using GC and LC. The extraction rates will be monitored GC-FID and LC-MS using techniques previously developed. Samples will be taken monthly as these reactions of interest generally occur on a fairly slow time scale.Our previous work indicated that there is little advantage to using smaller barrels, the standard 53 gallon barrel was chosen for all studies. In addition to tracking the aging reactions and extraction, storage temperature and humidity will also be recorded to look for correlations of environmental factors, in particular seasonal variations, to reactions.Perform economic analysis to determine the effect of possible yeast change on an industrial process.The data will be used to develop models for production and aging that will subsequently be used to develop process models for a more predictive approach to change in parameters.