The Daily Telegraph - Saturday - Saturday
Mrs Clay’s guide to household thrift This week... ready-made pesto
If you don’t have time to make your own, which jars are worth your while? Xanthe Clay reports
Oh, the fuss. When I mentioned online that I was doing a taste test of jarred pesto, I got a torrent of comments including “don’t do it!” and “make your own!”
Were they right? Would the pestos all be disgusting? Or was this, dare I say it, snobbery from the kind of people who holiday in Tuscany and follow River Cafe Cookbook recipes religiously? After all, we Brits buy 34 million jars of pesto a year and one in four households has a pot of it in the cupboard.
Nineteen jars later, I can tell you that none of the bottled pesto tastes like fresh pesto, any more than tinned tomato soup tastes like homemade. But that doesn’t mean that some aren’t very much better than others.
According to Sacla, the company that introduced pesto to the UK market in 1991, its own consumer taste tests indicate that we prefer to buy pesto that is salty and cheesy, not herby. This makes sense, as the flavour of basil, pesto’s key ingredient, is fragrant when fresh but turns bitter and soapy if it hangs around.
This can be made much worse by the addition of flavouring, which even if it is “natural flavouring” (not necessarily made from basil at all but from another plant source) can taste overpowering and deeply unnatural. There can be too much acid – usually lactic acid, used as a preservative – in many pesto products, leaving a sickly tang.
Better, then, to seek out jars which deliver on umami (an intense savouriness) and a subtle leafiness than those which taste medicinal or (as in the case of one I tried) smack vaguely of cleaning fluid.
The reality is that the jarred stuff is attractive because making pesto from scratch is expensive. Take Anna del Conte’s classic recipe, which involves 20g pine nuts, 50g basil leaves, a clove of garlic, 4 tbsp grated parmesan, 2 tbsp grated pecorino and 125ml extra virgin oil. Using the cheapest supermarket ingredients, and allowing for those shop-bought 30g bunches of basil being mostly stalk, it’s going to cost around £4 to fill a standard 190g jar.
Not that the ready-made versions use anything like those ingredients. Most include added vegetable fibre (often from peas) which provides cheap bulk to the mix. Potato starch features in some to balance out the sourness of the lactic acid. Then there’s sugar or glucose, neither of which is traditional in pesto recipes.
There are plenty of cost-saving substitutions for the core ingredients, too. Take the basil: some of the pesto I tried was fibrous to the point of hairiness, leading me to assume that a lot of basil stalk had gone in along with the leaves.
Classic pesto should contain a mix of Parmigiano Reggiano, a cow’s milk cheese, and mature pecorino, made with sheep’s milk. Some cheaper jarred versions replace the parmesan with grana Padano, a less expensive cow’s milk cheese also made in Northern Italy. It’s a good cheese, if a bit less complex than parmesan – but one to avoid if you have an egg allergy, as it is generally made with an egg-based preservative.
Most use cashews instead of traditional pine nuts: where pine nuts are included it is often so few as to be meaningless. Sacla, Filippo Berio and M&S Green Pesto, for example, all contain more salt than pine nuts, so I can’t believe they really add much to the flavour, though it does allow producers to say they’re including the classic ingredient. Talking of salt, back in 2017 there was uproar when it was revealed that some brands of pesto were saltier than sea water. While some have dialled levels back a bit, many are generally salt-heavy, and some contain three times the salt of others.
A quarter of a 190g jar (which is reckoned to be a portion by supermarkets) can deliver between 0.5g and 1.5g salt depending on the brand, so it’s worth checking the label carefully if you are concerned. With maximum recommended salt levels at 6g a day, that’s a good chunk, so don’t add any more salt to your meal.
And as for snobbism, the supermarkets play up to it with their branding. Cheaper jars are chummily called “Green Pesto” (to differentiate them from “Red Pesto” made from dried tomatoes); perhaps only shoppers with the cash to splash on posh pesto are deemed knowledgeable enough to comprehend “pesto alla Genovese”. Don’t be fooled: there’s good and bad in both camps.