Welcome to the Tasting Season. This is the time of year that all the supermarkets and a lot of the small retailers put on Press tastings. If this sounds like one long wine party, think again.

The supermarket tastings start at about 10am and there are usually 130 to 180 wines lined up on tables in some airy, bright central London venue. With a glass in hand and a notebook to record my thoughts, I usually start with the white wines, then cleanse my palate with a flight of fizz and then proceed to work through the reds.

Forget all the notions you may have about clearing the palate with a sip of water or a biscuit between wines. For me, that doesn't work and it would take too much time. With glass in hand I pour, swirl, sniff, slurp and spit, at a speed of about 40 wines per hour, making comprehensive notes as I go along.

This is my opportunity to taste whatever that supermarket has been working on during the year – new lines and new vintages. It gives me the chance to talk to the buyers and find out what has been happening in their sector. And if you are now imagining a wine tasting that you may have been to, with hundreds of people crowding around the tables – it isn't like that at all.

These tastings are generally quiet affairs, for the Press only. Often there are just a dozen or so people there – key wine writers for the nationals, major magazines and, of course, the Yorkshire Post. If the crowd gets to two dozen, it is really quite busy.

When I have reached the end of the tasting, usually avoiding the viciously-flavoured liqueurs that occasionally lurk at the end of the line, I have a quick run for the train and as I sit there among the other passengers I try not to smile or speak to anyone, lest they see my purple-stained teeth.

So with Asda, M&S, Sainsbury and Tesco already through the season and with just another few to go – how are the big players in this market riding the economic storm? Surprisingly well it seems.

Asda has done a complete revamp of their range. "We have just launched 250 new wines," said their head of product development, Philippa Carr, master of wine. "But that doesn't mean the range is bigger, in fact the overall selection is slightly smaller, mainly because we have removed duplication." And each wine has had to justify its place on the shelves. "We compared each wine within the market and made sure that whatever a customer has to spend on a wine, we provide the best we can for that price."

Now with clear country-by-country signposts within the wine department plus a much bigger rosé section and a changing selection of wines on a 3 for £10 offer, Asda thinks they are well placed to meet the challenge of the festive season. I have been fairly critical of Asda in the past – a few years ago I thought my tastebuds had upped and left me when I tasted through their range, but things have changed. Philippa has been in post for just over two years and is now making a substantial impact.

The Asda Extra Special range is really rather good. From the deep, lush fruit of Extra Special Coonawarra Cabernet Sauvignon 2005 (£6.98) which comes from the up-market Katnook Estate to the straightforward, apricot fruit of Extra Special Viognier 2007 (£5.98) from Paul Mas in the south of France, there were very few Extra Special wines that failed to hit the right notes. I particularly enjoyed the pair of New Zealand wines, both sourced from Wither Hills. The Sauvignon Blanc 2007 (£7.48) is bright and full of herbaceous fruit while the Pinot Noir 2007 (£7.98) is remarkable value, with soft, red fruit flavours and a finish well above its price point. Also good were the vibrant, spicy Extra Special Gewurztraminer 2007 (£6.98); the soft, almond-edged flavours of Extra Special Fiano 2007 (£5.98); the pure, minerally fruit in Clare Valley Riesling 2007 (£8.12) and the dense, damsony fruit in Extra Special Primitivo 2005 (£5.98). The labels on these wines are very discrete. Since wine is one of the few things we buy from supermarkets which remains in its packaging right up to the moment of consumption, I always think it is a grave mistake to put the name of the supermarket in bold letters. These Asda Extra Special wines have just a small band at the bottom of the label, so unless someone peers at the bottle they won't know where you bought it. The same cannot be said of Asda's Brut Champagne, which at £12.98 is cracking value, with rounded toasty flavours, but the Asda name is big and bold, so you'll need to wrap a napkin round to hide it.

At the value end of the shelves, Philippa seems to have discovered a few gems that will provide some good flavours without wrecking the weekday budget. The Asda South African Chenin 2008 at a bargain £2.98 is perfectly drinkable with light, floral fruit although the step up to Ken Forrester's Chenin Semillon 2007 (£6.12) provided masses more flavour.

Asda's Chilean Chardonnay 2007 (£3.17) was perfectly sound and fine for Monday to Wednesday drinking. I could even be persuaded to drink the own-label Montepulciano d'Abruzzo 2007 (£2.98) on a Thursday evening, although for weekends I would have to trade up to the Il Faggio version at £6.98. The Marqués del Norte Rioja 2007 at £2.98 is another well-made bargain, but the real flavours seem to have been reserved for the Extra Special version at £8.98.

Asda has even included a few fine wines in its range with top names such as Green Point, Cape Mentelle, Baron de Ley and Tokaji. Of course not everything was good at this Asda tasting. There were a few wines which just couldn't muster enough flavour to justify their price, especially from France where the rise of the euro against the pound seems to have had most effect, but if you have not bought wine from Asda for a while, maybe now is the right time to check them out.