Enology (winemaking) Research An Unusual, Attractive Senior Research Topic1 Frank J. Gadek Allentown College, Center Valley. PA 18034 Focal points of our upper level chemistry c u r r i d u m are two elective 3-credit research courses, CH 461 (fall) and CH 462 (spring). For the 6-year period from 1969-1974,7 of our 32 chemistry seniors (22%)elected CH 461 and often CH 462 as well. During this 6-year period, the research project in CH 461 and CH 462 involved organic synthesis of quinoline analogs. A t the end of this 6-year period, the research based on the quinoline analogs did not appear to have its old appeal, so a new approach to research was developed to accommodate these changing interests in a small liberal artsoriented college. In general, Allentown College has averaged 20-30 chemistry concentrators each year out of its approximate average annual enrollment of 600. During a one-semester sabbatical leave from the College covering the fall semester of 1974, the author initiated an enologv research oroiect in the hooe of attracting more students';~the reseamhenperienre offered by the department, as well as expanrlina his inwrest in the chemistry of wine. This project centered around three facets of wine made from locally grown grapes: 1. five methods of deacidification of these usually high acid
wines; 2. the effect of the use of pectic enzyme during vinification of these
wines; 3. the qualitative and quantitative composition of the total phenols
of these wines (e.g.,tannins, color pigments, etc.).
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Anoroximatelv 1.6 tons of 11locallv .. .erown French hvhrid grape varieties were harvested, vinified, processed, and bottled for this studv. The exoerimental wines oreoared for these O of 36 different hatches of studies totalred about ~ O gallons wine. At the time this study was initiated, little published work was reported on these three areas with respect to French hybrid grapes. Small commercial and amateur winemakers in the 3-credit CH 140 Science of Enology course that the author had been teaching (I) strongly expressed their need for extensive information in these three are& in order to make a quality product from these locally grown grape varieties. French hybrid grapes, as opposed to the European uinifera, are widely grown by these winemakers since they are more adaoted to the harsh climatic conditions of the northeast U.S. audcanada, and since many states require by law that local wineries use only grapes grown within that state.
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Division of Chemical Education, National Meeting of the American Chemical Society, Washington, DC, September 1979. Gverall. for the 12year period covered by this article (1969-1980), 18 of a total of 53 seniors (34%)and 3 juniors elected to take the CH 461 andlor CH 462 research courses (5 seniors elected to take both of these research courses). From 1969-1974.7 seniors and 1 junior elected the quinoline research project. The enology research project involved student participation from 1975-1980. For this 6-year period. 9 seniors and 1 junior elected the enology research project, but only 2 seniors and 1 junior elected the quinoline research project. 9ntercollegiate Studem Chemists Convention. Indiana, Pennsylvania. Mav 6~ ..~-,1 9 7-.
Second Annual Meeting of the American Society of Enologists/ Eastern Secton. Erie. Pennsylvania. August 1977. Third Annual Meeting of me American Society of EnokgistslEastwn Section. Erie, ~ennsylvania.August 1978. 654
Journal of Chemical Education
This new research project was also designed to increase the depth and breadth of the new enology program a t the College. This program would then consist of the introductory enology course (CH 140), an advanced course (CH 240, hased in part on the resultsof this research project and to be developed and taught when scheduling permitted), and the two research courses (CH 461 and CH 462). General interest in the material of this program was assured because of the great proliferation of amateur winemakers, small wineries, and small vineyards growine interest in wine in in the eastern US..as well as the " the country (I). Nominal funding and donations of material were obtained from the College, Chemistry Department, and local individuals and organizations. Personal funds and the use of a oortion of the author's orivate residence facilities were required for the completion OF the project. Student Participation in the Enology Program, 1975-1980
Over the 6-year period from 1975-1980,9 of the 21 chemistry seniors (43%) elected to participate in the enology research p r o j e ~ tAs . ~ time permitted, the students participated in harvesting the grapes, in the winemaking process, and in processing the wine (e.g., racking, bottling, etc.), as well as in the sensorv . (tastine) . -. analvsis (2). . . . and chemical analvses of these wines. The reauirements for these 3-credit courses included a 1 hour group conference and individual oral reports each week, a minimum of six hours of laboratory worklweek, hiweeklv to the department written lah reports, a final oral faculty, a final written report a t the end of the semester, and selected relevant readings and study. Grading involved 25% for the final oral report, 25% for the final written report, and 50% for the oral and written reports during the semester. Precision of the chemical analysis results was checked by havine each student analvze several dudicate wine samdes. The iientity of these samples was revealed to the students onlv after thev had comoleted their analvses and had submitted their rksu~ts.~ h grades d for the 9-students over the past 6 years were 6 A, 3 B, and 3 C (3 students took both of these research courses).
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Outcomes Three papers (one by a student) have been presented on the results of this work."5 In addition, a research note on the oreliminaw results of the deacidification studv has heen published (3).Funds (approximately $3,000) weie attracted to the College for this research in the form of mants and donations ofmaterials by local individuals and orghzations. An 830 Dupont High Pressure Liquid Chromatograph (valued between $25,000-$30,000) was donated specifically for the enology research program by Merck, Sharp and Dohme Research Laboratories, West Point, Pennsylvania. Students who did well in this research experience have sineled out this research as a maior factor in their success in positions as professional chemists after graduation. In addition. the Colleee. Deoartment. and these students received locai and n a ~ i & a ~ - ~ u h l i c i tbecause ; of this research project.
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Laboratory Techniques for Chemical Analyses of Wines and Musts
Laboratory Techniques Used
Table 1summarizes the laboratory techniques (4,5,6) used in the chemical analvses in this ~roiect.All of the listed analyses have been completed on allbf ihe 36 different hatches of ex~erimentalwine e x c e ~ sulfur t dioxide, tannin, ion exc&e chromatography, atomic absorption, and HPLC work. They encompass much of the theory and practice of chemistry generally taught a t the undergraduate level. In addition, the large numher of chemical analyses required by this project necessitated that the students become involved with some elementary statistics and data handling procedures, in coniunction with the oractical analvtical chemistrv concerns of precision and accuracy. The unusual and attractive nature of this research project greatly inspired and motivated these students to excel in this work (one student precisely performed over 1.000 chemical analvses on these wines in sliahtlv more than one semester!). Summary
The use of a practical enology research project in order to attract students to research at the undergraduate level and to increase the depth and breadth of the enology program a t Allentown College was more successful than anticipated. Senior chemistry students made use of much of what they had learned in our remlar chemistn, curriculum hv a .. ~ o "l v i n eit to an unusual and i k r e s t i n g areaof research. ~ c nature e of the topic inspired students to excel in the particular area of chemical analysis assigned to them, and it motivated them to master the theow and techniques involved. The partici~ation of the students in activities reiated to the produition or these experimental wines (e.g., harvesting, vinification, processing, etc.) enabled them to appreciate some of the practical considerations involved with producing a quality product. This participation helped the student put his or her role in the project in proper perspective with respect t o the problems associated with consistently achieving a quality product, especially in such a complex area of food chemistry. In addition. the enoloev research oroiect enhanced the depth and hreidth of the new enology iro&am at the College. This research eenerated new course information that aided those winemaGers who took the enology course in making better wine more consistentlv from locallv mown maws. Also, the tevhnical and scientific>ompetenceof the author in rhe field of enolow was enhanced so that he could not only better respond to the needs of the chemistry students a t theC!ollege who took the research courses, hut also could better f u l f i the needs of the many winemakers who took the enology courses.
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The author is grateful for the aid of the following: Allentown
Technique Hydrometry 6 refractomeby
PH Titretion: acidlbasa
Analyses taal soluble solids ( % sugar) In must (i.e., unfermented grape juice or whole crushed grapes) alcohol (aner regular distiilation) exbact (after regular distillation) oH of both wins and must
indicator) tannins (potassium permanganatel indigo carmlne indicator) alcohol (followed by hydrameby or Distillation: regulal refractametry) exmct (followed by hydrometry a refractometry) volatile acidity (followed by acbdlbase steam titration) detection of malo-lactic fermentation. Paper chromatography (conversion of malic acid to lactic acid by special bacteria) separation of malic and tartaric acids Ion exchange chromatography color (420 nm browning. 520 nm red Spectrophotomehy: visible color) total phenols malic acid, tartaric acid, lactic acid potassium, calcium atomic absorption residual reduclng sugars Colorimeby High pressure liquid chromatography colw pigments
College gave one-semester sabbatical leave and research grants. The Chemistry Department provided funds, facilities, equipment, and chemicals and the Mennonite Foundation, Shering Plough Pharmaceutical Company, Air Products, Inc., PQ Corporation, and the Research Corporation provided additional funding. Senior chemistry research students were exceptionally dedicated and gave the time and effort required t o make this research project a reality. Dr. Lois P. Gadek, English Department, Allentown College assisted in preparation of all enology manuscripts. Literature Cited
New York. NY,197b (6)
Webb. A.
D., "Cherni~tlyof Winemaking:
American Chemical Saeiety, Wuhington
OC, 1974.
Volume 59 Number 8 August 1982
655
