Alcohol on the brain? Not the best place for it perhaps, but rising levels of alcohol in wine are not just burning our throats but stirring the grey matter too. In California last year, Kent Rosenblum gave me a bottle of his 16.5 per cent zinfandel. When my wife, Charmaine, and I uncorked the monster, we found it was too thick to drink, so we diluted it with water (a practice commonly carried out at wineries, incidentally, to keep the alcohol level down). At what must have been more like 13 per cent, not only did we start to enjoy it (sorry Kent), but we'd managed to stretch it to a litre. I raise the subject because a number of readers are clearly finding excessive alcohol a bar to the refreshment and balance they're looking for in their wines.

Linda Ball, for instance, says that she has "a very eclectic and fairly experimental palate" (she isn't keen on chardonnay) but finds that her tolerance for alcohol has plummeted. Looking in Tesco recently, "the choice of lowish alcohol wines seemed pretty limited", so she wants to know what she can drink that's "a bit more inspired". Caroline Speck took me to task for including a 15 per cent alcohol white in my summer wines (although she admits to enjoying sipping a cool 15 per cent fino sherry as an apéritif). She wants to see more choice of wines at lower alcohol levels. "I think that in the drive towards higher alcohol content a great deal is being lost - not least the taste and quality of the wine," she says.

All the evidence points to the fact that alcohol in wine has been gradually rising from around 12 per cent in the 1970s to more like 14 per cent in many regions today. The increase may have something to do with climate change, but more tangibly reflects the fashion for smoother, richer wines. Higher alcohol in wine is a reflection of improved vineyard conditions. Grapes can be picked riper in the rain-free harvests enjoyed by many New World wineries, and pests and diseases are easier to control. Longer "hang time", as the Californians put it, adds to flavour and texture in a wine, at the same time cutting out vegetal characters and harsh tannins. On the down side, it increases sugar, hence alcohol. The challenge is how to achieve natural balance and "flavour ripeness" at moderate alcohol levels.

Balance is the key and some grapes lend themselves to lighter styles and vice versa. Taking a walk on the light side, German riesling can be balanced at around eight per cent and such relatively low alcohol riesling is one of the summer's great refreshers. Try, for instance, the deliciously juicy, sweet and sour 2002 Burg-Layer Schlosskapelle Riesling Auslese (8.5 per cent), £5.49, Majestic, or the spritz-fresh, featherweight 2004 Leitz Rüdesheimer Bischofsberg Riesling Auslese (7 per cent), 50 cl, Waitrose, or Dönnhoff's off-dry, 2004 Nahe Riesling (9 per cent), £8.69, Booths, with its delicate tropical lemon and grapefruit zest.

From Portugal, the vinho verde grape is often refreshingly tart as in the case of the thirst-quenching 2005 Quinta de Azevedo Vinho Verde (10.5 per cent), £4.99, Booths and Spain's jasmine-scented 2005 Torres Viña Esmeralda (11.5 per cent), £5.49-£6.19, Oddbins, Threshers, Waitrose, Tesco, is a fragrant dry Catalan cocktail of moscatel and gewürztraminer. Even the New World can produce classic lower-alcohol styles like the Hunter Valley's lemon-lime zesty 2005 Brokenwood Hunter Valley Semillon (10.5 per cent), around £8.99, Andrew Chapman Fine Wines (01235 821539), The Flying Corkscrew (01442 412311), Luvians Bottleshop (01334 477752), a young dry white that will refresh now and improve with age.