When you listen to wine buffs talk, there are phrases that get dropped casually into conversation that tend to result in a few knowing nods amongst the listeners. Like any good jargon its purpose is not so much to shine the light of understanding on the subject, but rather it's to separate the speaker from the common herd. You may have heard the phrase 'malolactic fermentation', a good example of wine jargon, and maybe even wondered what it meant.

Malolactic fermentation is a process which can occur in wine after the primary fermentation is over. By primary fermentation we mean that basic process whereby yeasts consume the sugar in the must and convert it to alcohol with carbon dioxide being given off as a by-product. This secondary fermentation can occur naturally and it involves the conversion of the grape acids. Wine grapes contain natural acids like tartaric acid and malic acid, which comprise more than 90% of all the acids in the grape. There is also a small amount of citrus acid, as well as other some other components in small quantities.

It's the acid level in any drink that gives it freshness - that's what gives lemonade and fruit juices their bite. Of all the grape acids malic acid has the harshest taste. It's the same acid that you find in unripe green apples, that same acidity that makes you want to pucker your cheeks. During the process of malolactic fermentation, enzymes convert the malic acid to the softer lactic acid. In cold regions where grape acids, particularly malic acids, are at high levels, then malolactic fermentation is desirable and is encouraged by the winemaker since it softens the wine. In warm climates, grapes are riper and acid levels in wine tend to be low - so it's desirable to keep the malic acid and in this case, malolactic fermentation is prevented.

Malolactic fermentation also deepens the colour of the wine, lessens the fruity fresh flavour and increases the buttery, viscous mouth feel. Hence, a wine which has been through malolactic fermentation will taste older and richer than it really is.

Wine of the Week

Underhill Semillon/Chardonnay 2002

At a recent wine tasting this wine positively shone out. It has the rich buttery, creamy taste that we associate with a good Chardonnay, it has a very lush mouth feel and if you were guessing at its price you'd probably guess double its actual cost. The pleasant surprise as we come up to Christmas and party time is that it's on special offer in O'Brien's - 2 bottles for €10. There's a Cabernet Sauvignon from the same house and it's priced the same as the white. A perfect Christmas party wine.

Wine Notes

The 2004 Wine Guide is out, yours for €12.90. It's edited by John Wilson and covers most of the popularly-priced wines on sale in Ireland. It's well-laid out in a pocket sized format and it's easy to find any one of the nearly 2,000 tasted wines. Simple, clear tasting notes condensed from a large panel of independent tasters make this an invaluable guide.