In his lively and instructive book, “Essential Winetasting,’’ Michael Schuster, a British educator, offers an exercise designed to show how fruit, acid, and alcohol combine in wine to deliver a complex taste experience. His technique involves mixing three water solutions.

One with sugar, one with lemon juice, and a third with vodka  and tasting them first separately and then in various combinations. Isolating the sensations peculiar to each element really helps you think about what each contributes  and how they may combine to produce harmony in the glass. Wines showing this sort of good character are sometimes said to observe the classical proportions.

Wine may show signs of being unbalanced when acidity is too low to counter the sweetness of fruit, or when alcohol levels rise to the point where they produce a sensation of heat. Sometimes balance issues are the result of anomalous conditions in the vineyard, but they may also be traceable to how wine is worked in the cellar (think of all those California chardonnays bent low beneath their burden of oak).

Shapely, appropriately scaled wines are appetizing and versatile. They won’t readily pick a fight with what you’re serving, and you can drink them night after night without fatigue. Find a single red and a single white with these characteristics and you’ve got a pair of friends that can take you right through a whole season of weeknight meals with flying colors. Now that’s what we call chemistry.

Chidaine “Val de Loire Sauvignon’’ Touraine 2008 Forward but not obtrusive sauvignon-esque aromas; mouth quite ripe with some tropical and piney elements; bright acidity; nicely crisp; some mineral notes. Serve as an aperitif with goat cheese and wheat crackers. Around $12. At Curtis Liquors, South Weymouth, 781-331-2345; Groton Market Wine & Spirits, Groton, 978-448-6387; Formaggio Kitchen, Cambridge, 617-354-4750.

Cono Sur Colchagua Valley Viognier 2009 Somewhat sweet floral aromas; nice round, full mouth; fine steady ripe fruit; adequate acidity. Goes with BLTs, tuna salad, pasta salad, mac and cheese. Around $10. At Brix, South End, 617-542-2749; Cambridge Wine & Spirits, 617-864-7171; Curtis.

Domaine de l’Ameillaud Vin de Pays de Vaucluse 2007 Modest aromatics; pleasantly light-bodied with easy-going red fruit, laid-back texture, and a bit of loamy earth. Pour with pasta and fresh tomato sauce or a bowl of minestrone. Around $8. At Berman’s Wine & Spirits, Lexington, 781-862-0515; Foodie’s Urban Market, South End, 617-266-9911; Curtis.