A month ago, at the Abergavenny Food Festival, 50 people and I spent an hour or so discussing the fundamental principles of Bloody Marys. And then we tasted a trio of them. Or, more accurately, I did most of the talking and they did most of the tasting. I know I had a good time, and I think they did too.

A Bloody Mary is a type of punch: ie, a cocktail based on fruit juice with extra flavourings and alcohol. And when you're making a drink like this, the idea of balance is vital. You can say the same thing of any cocktail, but balance has a particular meaning in Bloody Marys because many people lose sight of it.

In its simplest form it contains just five ingredients on top of the juice and vodka: Worcester sauce, chilli sauce, lemon, salt and pepper. Misguided Mary-makers often err in two directions. One, they put in too little lemon. Two, they turn it into a fiery drink - what I call a Vindaloo Mary. This may be good for people who like to sweat. It is not good for people who like to drink.

Proceeding cautiously - adding flavourings to tomato juice little by little, tasting all the while - is always your best bet when making Bloody Marys. You will eventually get to the right proportions. If you want a starting point, however, you can use my formula. I've published it here before, but not for several years, so I don't apologise. For four drinks: 25ml lemon juice, 2.5ml each of salt and freshly ground black pepper, 30ml Worcester sauce, six drops (around 0.5ml) chilli sauce, 450ml tomato juice or V-8, 150ml vodka. This is strong on lemon, which is the way I like it, and I think you will too.

But it's important not to get fundamentalist about Bloody Marys. When I asked for a perfect recipe from Richard Hunt, the extravagantly gifted head bartender at the Player in London W1, he dismissed the notion. "There are so many variations. It depends on my mood, the time of day and year, and how bad my hangover is." Wise words. The only truly essential rule is that the ratio of vodka to juice must be fairly high. Though some recipes give it as high as six parts juice to one part vodka, 2:1 is better and 3:1 is ideal.

As a matter of principle and of pleasure, I always advocate making Bloody Marys from scratch. But one ready-made mix makes a fantastically good substitute, and that is Big Tom. It's a complex mix with a lot of exotic spices, and my audience at Abergavenny approved mightily. Big Tom is pretty widely available, though you can also order it online ( www.bigtom.co.uk).

I used to think that in a strongly flavoured drink like a Bloody Mary, the quality of the vodka is a secondary consideration. Well, I was wrong. At Abergavenny, I had on hand three vodkas generously donated by Sainsbury's, which sells what I believe is the largest vodka selection of any UK supermarket. The three were Sainsbury's own-label (£7.49), Finlandia (£12.99), and the Icelandic Reyka (£15.99), about which I have written in these pages before. They represented, roughly speaking, the ordinary, premium and super-premium sectors of the vodka market.

I made identical Big Tom Bloody Marys with all three vodkas and asked the audience to vote on their favourites in a blind tasting. The results were: 30 preferred Reyka, nine preferred Sainsbury's, and seven preferred Finlandia. While I believed Reyka to be the best of the bunch from my own tastings, I admit to some surprise - and a good deal of pleasure - at the overwhelming outcome. What's more, those who preferred Reyka thought it was worth the extra dosh. So I have one more rule for Bloody Mary perfection: use a really good vodka. If you're anything like my companions at Abergavenny, you'll notice the difference.

Three robust reds

Winemaker's Lot Malbec 2005, Concha y Toro (£6.49, Oddbins) If Chile keeps making such smoky, plummy, deeply concentrated wines from Argentina's signature grape variety, Argentina had better watch out.

Plan Pégau, Côtes du Rhône (£8.95, Lay & Wheeler, 0845 330 1855, www.laywheeler.com) Declassified Châteauneuf-du-Pape grapes from a fine producer, using a blend of vintages. Soft spice, ripe tannins, serious stuff.

La Cuvée Mythique 2002 (£4.99 from £6.99 until 22 October, Co-op) Solidly reliable wine from the Languedoc, using a blend of mostly local varieties. The discount price is a steal.