Winemaker’s Bookshelf


Experts explore the various technologies that evolved to producemost of the sweet wine styles we recognize today.


recently enjoyed reading Sweet, Reinforced and Fortified Wines. Grape Biochemistry, Technology and Vinification (ISBN 978-0-470- 67224-2 John Wiley & Sons, 2013). I liked their history of sweet wines in the Mediterranean Basin. Today, sweet wines are dessert wines but they were once the mainstay of wine commerce, stable during a sea voyage and could be stored between vintages. Dry wines were subject to


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microbiological or oxidative spoilage, and were mostly consumed locally. Sweet wines were treasured, but because of their intense flavour and high alcohol, were always diluted with water when consumed.


The 25 chapters of the book were the contribution of more than 30 international academics, winemakers, and journalists. The chapters are validated with up-to-date references documenting primary sources. There are several fundamental factors that affected the development of trade in sweet wines. The first is the combination of grape variety and climate which supports high sugar content prior to harvest. The second is an accessible harbour for shipment by sea. The third is technology, which would produce a stable product with enough alcohol and residual sugar to resist further fermentation or spoilage. This book explores the various technologies that evolved to produce most of the sweet wine styles we recognize today.


I enjoyed the discussion of word relatedness stretching back to 3000 BC among the various language groups. It demonstrates not only the early adoption of wine technology but also the ubiquitous distribution of the technology. One that especially interested me was the origin of the word ‘symposium’, from the Greek. This was a ritual in which a group of


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By Gary Strachan Learning from the history of ‘sweet’


men assembled for a ritualized feast centred on drinking wine. Formal dinners are still often part of a symposium, but without wearing garlands and being served by slaves. Over the millennia, winegrowing has


advanced and retreated with climate change. Civilizations have disappeared because of desertification. During climatic cycles of heat, viticulture extended to higher latitudes and higher altitudes, only to be abandoned during the following centuries when the climate cooled. The way in which must was concentrated,


sweetened or fortified was not only essential to the stability of the wines but it created product


differentiation between wines from different regions. Many of the old practices are still in use today to produce aperitif or dessert wines. The book has an interesting history of the rise and fall of commerce of wines from various regions since the Middle Ages, and the events that shaped wine trade and fashion.


There is a good discussion of the viticultural prerequisites required for the production of sweet wines. These include appropriate varieties for various styles, and vineyard location and management.


In order to obtain high sugar content within an average growing season the vineyard must not be overcropped, the variety must ripen within the appropriate season length and there must be enough heat throughout the season.


There is a good discussion of the factors affecting the accumulation of secondary metabolites, such as terpenes and phenolic compounds. With the exception of botrytis affected wines, the vineyard must also be free of infections if the grapes are to harvested late.


Historically, the sugar present at harvest was augmented by the


addition of honey, dried figs, raisins, or heat concentrated must. Other strategies were to twist the canes or dry clusters in the sun. Preservatives such as resin, herbs or spices have been used for centuries. In the past, some countries considered these additions to be adulteration and banned such wines because the strong flavours can cover up defects such as volatile acidity, oxidation, or moldy notes. Augmentation of wine by the addition of distilled spirit was developed from the 12th century onward.


There is a good discussion of the physiology and biochemistry of berry dehydration, both preharvest and post harvest. This includes not only the factors affecting moisture removal but also the factors that affect flavour retention and synthesis, especially with regard to volatile


compounds and phenolic compounds.


I especially liked the


chapter dealing with the management of vinification to preserve aroma. One large table listed the compounds which relate to specific flavours and another figure contrasted the changed aroma notes as they relate to sweet or dry wines from the same grape variety.


No review of sweet wines would be complete without a discussion of osmophilic (high sugar loving) yeasts. There is a good discussion of the changes in expression of the fermentation pathways, and speculation that non-Saccharomyces yeasts such as Kloeckera apiculata may eventually be a better option than fermenting with Saccharomyces cerevisiae. The chapter on yeast physiology is followed by a discussion of the changes effected by Botrytis cinerea, noble rot.


The last half of the book is devoted to discussions of 10 representative sweet wine styles, ranging from Amarone to Vin de Paille. For those considering the production of sweet wine, I highly recommend this book as an up-to-date reference.


— Gary Strachan’s profile is posted on LinkedIn.


British Columbia FRUIT GROWER • Winter 2013-14


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