Guide to tannins in wine Tannins in wine tend to have a bad press but is it justified? This blogpost takes a look at exactly what tannin is and how you can detect it in wine, which wines are the most tannic and which the least and how levels of tannin can be altered during wine-making and during ageing from the effects of oak. I’ll also cover the best foods to match with tannic wines and try to answer whether tannins are good or evil. Firstly, let’s look at how to detect whether the wine you are drinking is tannic. HOW TANNINS IN WINE TASTE It is in fact impossible to describe the smell or taste of tannins. It is easier to detect them through the sensations they create in the mouth… When taking my Diploma in Wine & Spirits I asked almost every lecturer and wine expert that came to talk to my class at the Wine & Spirit Education Trust how tannins can be detected and measured particularly as we were expected to describe tannins with words such as ripe, soft, green, stalky, chewy, coarse and fine-grained. It is very hard to describe how tannins can be measured and there were a lot of attempts to answer my question but the best explanation came from Michelle Cherutti-Kowal, now a Master of Wine, and it helped immeasurably in my general understanding of tannins and in those descriptions required for the blind wine tasting exams. Here’s how to tell if a wine has tannins and what kind of tannins they are. When you have a small amount of wine in your mouth, keeping your mouth closed, carefully rub your tongue over your top front teeth. With a tannic wine you can feel a bit of roughness on the teeth. Try it with several different wines and you will begin to be able to differentiate between coarse- and fine-grained tannins, wines with finer tannins feeling slightly smoother on the teeth than those with coarser tannins. In addition tannins leave you with an astringent sensation in the mouth, astringency being detectable by a mouth-puckering dryness on the inside of your cheeks such as you would get from sucking on a lemon. This feeling is caused by tannins interacting with proteins in the saliva; this interaction dries out the mouth. Some say that tannins create a bitter taste but in fact it is astringency evidenced in highly astringent wines by a chalky, powdery feeling in the cheeks but in less astringent wines with balanced or low tannins by a smooth silky texture. WHAT ARE TANNINS IN WINE? To understand tannins in wine and the effect they have, it helps to know where tannins come from. Tannins are found in many plants like the vine, tea plants and rhubarb. On the vine they are concentrated in the skins of grapes but are also found in the pips and in the stalks and leaves of the vine itself. Without being too technical, tannins are natural compounds and as mentioned above they react with proteins to make an unpleasant astringent sensation, thought to be nature’s way of deterring animals from nibbling on some plants. I am often asked if white wines have tannins. In fact since all grapes have skin and almost all have pips, all wines have tannins but to varying degrees. And in general white wines and rosé will have fewer tannins but the level of tannins depends on a number of factors – all of which I expand on below – such as the amount of time on the vine before harvesting, the grape variety itself and on the wine-making process. In the vineyard as grapes develop and ripen in the sunshine and warmth, the tannins in the skins and pips soften and become less astringent. Grapes grown in warm climate wine regions have more chance of creating wines with softer tannins than grapes grown in cool climate areas. The best time to harvest black grapes isn’t just about reaching the optimal level of sugar and acidity in the grapes but also about making sure the tannins are ripe and not too “green”. HIGH TANNIN WINES Some grapes are naturally higher in tannin than others. Grapes that are particularly high in tannins (often thicker-skinned grapes) include Cabernet Sauvignon (think of young Left Bank Bordeaux wines), Shiraz, Sangiovese, Nebbiolo, Malbec and Pinotage. But bear in mind that this does not mean that all wines made from Cabernet Sauvignon for example will display high levels of tannins because so much depends on the vintage and on the way the grapes have been treated in the vineyard and in the winery. In general younger red wines will have harsher tannins than aged red wines but, if they are well-made wines, their tannins will soften after ageing in a vat or in bottle. LOW TANNIN WINES Grapes that are naturally low in tannins include Pinot Noir, Dolcetto and Gamay. In a similar vein this does not mean that all Gamays for example will be low in tannins because winemakers could for example ferment and age the wine in new oak barrels, the effects of which are explained below. Grenache and Merlot are fairly low in tannins. In general white wines have lower levels of tannins because of the way they are processed during wine-making. TANNINS IN WINE-MAKING Tannins change during the wine making process and during ageing but the chemical process is still not fully understood despite numerous research projects. Aside from the ripeness of the tannins when the grapes are picked, the following can have a significant effect on the level of tannins in wine: – The length of time the grape skins are in contact with the juice and whether the grape stalks are included during maceration. In making red wine production it is essential to extract colour and flavours from the skins of the grapes and therefore tannins are unavoidable. The key is not to over-extract. For white wine the juice of the grapes is