Phillip Crews University of California Santa Cruz. 95064
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The Chemistry of Wine An introductory lecture-Iaborafoty course for nonchemistry students
A great deal of attention continues to he given to the improvement of methods for teaching chemistry to the nonscientist. A number of innovations in this area have centered around courses relating chemistrv t o environmental, social, and nutritional pmhlems (1-21.While not denying the need fur this anornach ir has been our experience that such cturses can be unsatisfying in several respects. The major difficulties stem from the nonhomweneous hackpounds of students who are attracted to this type of c o u r s e . ~ h a t coupled , with the enormous amount of relevant material to he discussed, can easily result in a rather shallow coverage of many chemical T W years ~ ago we sought to develop a vehicle for presenting chemistry in reasonable scientific detail to an audience of nonchemistry students. In order to make this course appealing we felt that a common-interest starting point was needed. We therefore develooed. . . and have successfullv. taught, .. . a course which focuses on a single topic-the chemistry of wine.' Combining weekly tasting sessions and laboratory experiments on wine making methods, this course arouses much enthusiasm from nonscience students; yet it subjects them to a rigorous experience with a limited number of chemical topic^.^
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Course Oraanization 'I'hr heart o r our nrlirSF i.; it; labc,rati,rv, for it is there that t hwrv lo oractice. We swnd several class t h ~students , red~~ct. weeks introducing students tithe chemistry laboratory. This involves practicing on standard samples, the basic analytic ttn.l~oiqu~s ( t a b l e ; ~ r m ~ i nirom g simple arid measurem&, to quantititr;iri~ms.distillatiI trJSIC dw;tanding o f the scientific prinriplrs ol w n r production. The lecture prw id?< an uppcflrtu~~it!. to discuss t o p i r from imwpn~c.orpnic, :lnd hchemistry as they relate to the wlnv makinr Dwcess t / ( , - I 1 1. 'l'imt: is also devotrd to nsoects of w k e other than the strictly chemical. For example, a.discussion of the botany and biology of the grape itself includes a description of the location of various chemical entities and the chemical chances that occur during-rioeninn . - (12). The topic of "post-fermentive variables" leads to a consideration of the varietv of microorganisms which are oresent in wines and their effects [both harmful andbeneficial) on wine components (11,13). Finally, a discussion of aging techniques (11, 14) offers an opportunity to subject a number of widely held ideas (some of which are based upon a minimum of scientific study) to close scrutiny. In the context of this last matter, we find that some solid points can be made about the uses and misuses of scientific methods. The enological literature includes many studies which attempt to quantitate the effect of taste on such variables as soils in which the grape was grown, climate of the region in which the grape was grown, pruning methods used on the vines, fermentation temperature, type of wood in which the wine was aged. etc. It has been our observation that manv such studies are poorly devised and controlled, and that the conclusions drawn from them are often unsubstantiated. It is quite valuable to make the point to students that many seemingly scientific studies do not achieve an unequivocal conclusion. We point out possible errors in published studies and are able to drive home the fact that a great amount of care and planning must go into a proper experiment. n .
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No course dealing with wine would be complete without tastine sessions. and ours are normallv held once each week in thekvening. We begin the first session with a neutral white wine which has been doctored with small hut nerce~tible . amounts of chemicals often found in poorly made winesglycerin, ethyl acetate, excess SO*, excess tannins, excess acidity (both volatile and nonvolatile). With this introduction, students often develop remarkably perceptive palates and become able to distinguish individual chemical components in wines. We then proceed for the duration of the tastine sessions with inrroductiou of the rnujur wrietal tvpes in California: Ziniandel, Caberner Sauviynon, Pinot h i r , Chardonnav. I. " , White Rieilinr. -, S n u v i"r n m Hlanr 112. , , 1Fj , In conclusion, we have found this course on the chemistry of wine affords a popular and interesting vehicle for exposing nonscience students to an in-depth scientific study. It is our hone that bv taking this course. our students will not onlv I)trwnt: knc~wlrtlyw~l~lr a l n ~ the t fascinating field uf wine, but ;tlw will rain ;I rntliitic imnrebsion of rhv sktll and core which go into &vising and carriing out accurate chemical experiments. In addition we feel that the organization described
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above maximizes the chances that nonscience students will come away from an introductory chemistry offering with a strong feeling for proper scientific methodology. Literature Cited I l l Fuller. E. C.J. CHEM. EDUC.,51, 2MI (19741and IiLeraturecitstinns1-17 within. (21 l'rurnhnre, C. N.,J. CHEM. RDIIC.,52.450(19751and litersfweeitations 1-23 with-
I61 Amerine. M.A..Sri.Am
