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together beer and wine. Released once a year, the range features a pilsner and Sauvignon Blanc hybrid and a golden ale with Muscadel, one of the oldest grape varieties in South Africa used for sweet dessert wines. Folke & Goode’s Fresh Harvest is a Berliner Weisse brewed with freshly crushed and pressed Sauvingon Blanc grapes and Hallertau Blanc hops, a German variety that imparts an aroma of tropical fruits. The brewer is Fraser Crighton, a trained winemaker and sommelier, and the brewery is a stone’s throw from the wine cellar at Black Oystercatcher Wines in Overberg. Fraser was also instrumental in creating an IPA with Red Muscadel in collaboration with Stellenbosch Brewing Co as part of the global Brewgooder movement to help tackle the worldwide water crisis. While there are many other pioneers on the vino-esque beer scene, it is worth noting that Brasserie Cantillon, the world acclaimed Lambic brewer in Brussels, in the 1970s used Muscat grapes and produced ‘druivenlambik': grapes lambic. In 1987 the name Vigneronne Cantillon was given and since then organic French Viognier grapes have been blended with lambics aged for 16 to 18 months to make Vigneronne. Cantillon has also been making Saint Lamvinus since 1995. Saint Lamvinus is a blend of lambics aged for 16 to 18 months and Merlot grape from the Côtes de Bourg region in Bordeaux. The grapes are soaked for around eight weeks to allow the lambic to extract the grape tannins. The latest blend, bottled in November 2022, is made with Merlot (55%), Grenache Noir (35%), and Syrah (10%). FERMENTING FLAVOUR It is well documented that wine yeast will not perform as predictably as brewing yeast in a beer recipe. It can, however, be persuaded to add aroma and flavour to create distinct tastes. That said, most wine yeast strains are killers! They produce toxins which are lethal to brewing yeast and to other microorganisms. They produce both a killer factor and an immunity factor and will kill and outcompete other yeasts. Wine yeast is also faster fermenting and produces higher levels of alcohol. Is there a difference between wine yeast and beer yeast? The genetic differences between wine yeast and beer yeast have diverged over time with both winemakers and brewers unconsciously selecting variants best suited for their purposes. Brewers place greater emphasis on consistency and stability; in contrast, wine is a product of variability; of season, terroir, and the fermentation that ensues. The variability of themicrobiota in the vineyard and cellar introduces a factor of unpredictability into the sensory characteristics of the wines produced each season. Also, winemakers do not rely on collecting and reusing the yeast batch to batch. While wine and beer yeast share their origins, beer yeasts are more specialised. Over time specific genes have been deleted, especially those that lead to undesirable flavours, while others are amplified for optimal fermentation and positive taste profiles. An example of this is the selection for phenolic off–flavours (POF). The POF gene codes for an enzyme that catalyses a reaction where the compound ferulic acid–an antioxidant found in barley malt, wheat bran and in other cereals–is cleaved during fermentation, leaving 4–vinyl guaiacol (4VG), an aromatic compound that will give beers a spicy, clove – like, almost medicinal flavour. POF is reduced in all beer yeast strains except in Bavarian wheat beer strains and in Belgian and French Saison yeasts where the phenolic flavour is desired in these styles. Interestingly, some wine yeasts are POF+ (positive), but it is the production of 4VG by the yeast Brettanomyces bruxellensis , that is a major source of wine spoilage, especially in white wine production. In red wines the POF+ character is inhibited by the phenolic acids present, and that is because red wine on average contains over six times as much compared to white wine. Wine yeast plays a key role in the aroma profile of wine. The yeast enhances aroma by releasing aroma- active compounds called thiols (or polyfunctional mercaptans). These are powerful aroma compounds formed from precursors present in the grape must. Wines made from Sauvignon grapes and other aromatic white grape varieties are rich in aroma-active thiols, which impart floral fruity notes, but the grape itself has predominantly the precursor or bound forms. That means a biochemical reaction needs to happen before they can become aroma-active. Their release is linked to a yeast gene called IRC7 which encodes the enzyme beta-lyase which is responsible for cleaving thiol precursors to release the aroma-active forms. It is a process called biotransformation. In contrast, most brewing yeast strains lack this gene. In fact, it was only relatively recently (early 2000) that polyfunctional thiols were discovered in hops and is now generating considerable interest amongst brewers. A challenge that brewers face is the introduction of grapes, must and grape juice at various stages in brewing. Acids in the grapes need to be modified. For example, tartaric, malic, and citric acid found in grapes affects the acidity, colour, taste, and stability of the wine, and so also the beer-wine hybrid. Post- fermentation acid-to-tannin balancing is common in winemaking. Phenols in grapes are sensitive to oxidation and will affect astringency and bitterness. And if that were not enough, using grapes and must in a brewing process introduces new sources of microbial contamination that will lead to off-flavours and reduced freshness. A bunch of grapes will have its own set of wild yeast and bacteria on them compared to that found in the typical raw materials used for brewing that include barley, malt, hops and adjuncts (alternative starch sources). The beer-wine brew could go sour or wild if the ‘contamination’ in brewing terms is not managed. BEER WINE BEER-WINE FUSION FUTURE With further understanding of the complexities of combining brewing and winemaking techniques, and of yeast functionality, fermentation, aroma and flavour development, the possibilities for beer-wine fusion drinks are endless. Add to these evolving consumer preferences, such as lower alcohol, reduced sugar, natural ingredients, and sustainability, the potential for innovative beer-wine fermented drinks becomes an exciting space. And, with continued interest from consumers and drinks producers in novel blends of aromas and flavours, innovative cross-category beverages are especially alluring–as is enjoying a beautiful vista of vineyards alongside golden fields of barley, while sipping on a oenobeer. 24 | Winter 2023 | ontapmag.co.za