Acidification of wine is more common that people think. So why don’t we talk about it? By Lisa Egan
Winemakers wax lyrical about how cooling breezes, planting at elevation and judicious picking contribute to the freshness of their wines. It all boils down to acidity – which, alongside alcohol, tannin and sweetness, is integral to a wine’s flavour profile, balance and structure, and contributes to its overall character and quality.
It also affects its ageing potential and how wine tastes and interacts with food. Without it, a wine can seem flat, flabby and unbalanced. But what is it and what do winemakers do if it’s lacking?
Acids occur naturally in grapes, the most prevalent being tartaric, malic and citric, and some wine grape varieties have inherently higher acidity than others. Levels of acidity are influenced by heat, with grapes grown in cooler climates generally having higher acidity (and a lower pH) than those in warmer climates. So an Argentinian Malbec will typically have a lower natural acidity than a French wine from the same grape, because each country’s climate affects the acidity level in the fruit.
Most wine enthusiasts know this, but what’s less well-known, at least by the average consumer, is that many wines have gone through an acidification process to increase the overall level of acidity. The procedure isn’t just permitted in many countries, but widely accepted as part of the winemaking process, just like fining or chaptalisation.
It’s rarely mentioned or referred to in discussing a wine’s qualities, and you’re unlikely to find a producer extolling the benefits of adding tartaric acid. So who’s doing it and is there anything wrong with it?
Giles Cooke MW, founder and winemaker at Thistledown Wines in Australia, says there’s more value to acidity than what we detect on the palate.
“As well as increasing the freshness and balance, I’d argue that the main purpose of acidification is to reduce the pH of the wine for a healthy environment for fermentation, because high pH ferments are at risk of microbial faults,” he says. “It’s extremely common in regions where it’s legal, and for many red wines grown in warm climates it’s almost de rigeur.”
Peter Mitchell MW, of Jeroboams Trade, agrees. “In warmer climates, by the time grapes have reached physiological ripeness, the levels of acidity can be too low and the pH too high for the wine to be balanced and there’s a risk of microbial instability and spoilage. In these circumstances, acid adjustment is all but essential.”
Mitchell also points out that acidification can enhance the effectiveness of sulphur dioxide, increase colour stability and protect against costly wine faults. “And if done correctly it should make a more stable, balanced and better-tasting finished wine,” he says.
Given the temperature influences on acidity levels, historically acidification has mainly been carried out in hotter regions. But it’s increasingly common in cooler places where climate change is causing higher temperatures to the detriment of traditionally planted grape varieties.
Chris Piper, of Christoper Piper Wines in Devon, says: “More sunshine hours mean that grapes are ripening with higher alcohol levels and beginning to show a lack of freshness.” As Peter Mitchell at Jeroboams notes, some popular international varieties aren’t necessarily suited to the changing climate.
But it’s not all about climate-related temperature. Places with a high potassium content in the soil – and therefore in the grapes – can produce wines with adequate acidity, but a high pH, owing to the exchange of ions between tartaric acid and potassium. Peter Mitchell again: “In these cases, despite having a high level of acidity already, it might be necessary to acidify to get a low enough pH for stability. Burgundy has had issues with high potassium levels in some sites, as have some Australian vineyards.”
When the fruit arrives at the winery, the grape must is analysed, taking account of total acid and pH, and a decision will be made about what addition is required to get the pH to a safe level for a healthy ferment: usually around 3.7 or below. It’s then a fairly simple process of dissolving tartaric acid crystals in the grape must and fermenting as usual.
Can you tell if a wine has been acidified simply by tasting it? The answer seems to be somewhere between “no” and “it depends”. Mitchell and Cooke agree that if the process has been too heavy-handed – or worse, carried out post-fermentation and not fully assimilated – the acidity might feel a little detached from the palate with a hardness that’s at odds with the ripeness. But if the adjustment was modest and done early, it’s unlikely anyone will be able to tell.
So what’s the problem? As with many things in life, it appears to be a question of perception, both in the industry and among the public. All of the experts we spoke to referred to a certain mystique, not to mention marketing value, to the perceived “naturalness” of a wine.
“Most drinks are heavily manufactured,” Mitchell says, “so wine is somewhat unusual in that much of it is remarkably unmanipulated and the adjustments that are allowed – at least for wine sold in Europe – are very limited and strictly controlled.
“The occasional adjustment after a difficult growing season would seem to me to be sensible. But consumers know very little about how their food and drink is made and preserved, which leads to a potential knee-jerk reaction when the word ‘additive’ comes up.”
Ben Witchell, winemaker at Flint Vineyard in Norfolk, says that while acidification isn’t something English vineyards generally need to do (in fact it’s illegal in most years) there are a lot of adjustments in the winery that the consumer won’t be aware of. “But not all of the additions we make are corrections,” he says. “Is dosage a correction? If so, all Champagne is corrected. What about using SO2? I have a basic rule that if I’m not happy to put it on my label then I won’t do it.”
Which brings us to labelling. If acidification is a common practice, and it’s seen by experts as a prudent adjustment, why is no one being transparent enough to admit to it on their label? Actually, some winemakers are, but they’re few and far between.
Ridge in Sonoma is one of just a handful speaking plainly about wine adjustments. Its website states: “We talked a lot about the honesty factor. We were going to make an honest label, and all the information that a real wine lover would want was going to be on it.” True to its word, water, calcium carbonate and tartaric acid are included in the Ridge ingredient list when they are used.
Here in the UK, the Co-op has pioneered consumer-friendly wine labelling, with its own-label wines listing tartaric acid when it’s been added, alongside sulphur dioxide as a preservative and bentonite, used in fining. But there’s a long way to go before most producers follow suit.
Why the reluctance to be open? “There’s a sense that wine is – or should be – one of the most unmanipulated consumable products out there,” Mitchell says, “and that by adjusting a wine it could be said you’re potentially losing some of its uniqueness and its sense of terroir – that the wine is in danger of being just another manufactured beverage. This is what I suspect leads to an unwillingness to talk about adjustments.”
Cooke goes a step further, suggesting that some producers are reluctant to admit that they have the wrong variety in the wrong place, picked too late, or their climate has warmed to a degree that the varieties planted no longer suit. Witchell also picks up on this, saying that intervention in the winery isn’t always necessary unless the winemaker is aiming for a style that’s not right for their fruit.
So is there a sense that it’s cheating? “I guess that depends on your personal philosophical standpoint,” says Mitchell.
Cooke agrees. “I think most serious wine producers these days would use as little in the way of additives as possible – both from an ethical/aesthetic perspective but also from a commercial one, because they all add costs,” he says.
“But it can be the difference between a correct and a spoiled wine. Within limits, there are things that you can do to mitigate against the use of acid adjustments – earlier picking, using high-acid varieties, acidic juice, selected yeasts, etc. For any pragmatic winemaker, it’s a useful tool to have – but shouldn’t necessarily be part of the ‘recipe’.”
