Trend Watch: The Power of Sour

The ingredients retailer, souschef.co.uk, saw sales of balsamic vinegar and yuzu soar in 2021. Balsamic vinegar was up 80% compared with 2020 and yuzu – fragrant Japanese citrus juice – up 57%. 

We counted more than 35 brands of the lemony spice sumac on Amazon. A surprising number of the products in Waitrose Cooks’ Ingredients range is sour: chaat masala, amchoor, black limes, pomegranate molasses, kalamansi juice and tamarind paste. 

Talk us through them.
Certainly. Made from dried, pulverised green mangoes, Amchoor is used in north Indian cooking to give recipes fruity tartness without increasing moisture. It’s a key ingredient in the spice blend that is chaat masala. Think of black limes as the Persian equivalent of preserved lemons. Kalamansi or golden lime juice is popular in Vietnamese, Malaysian and Philippine cooking. 

Tamarind makes Worcestershire sauce and HP (brown) sauce more-ish; it’s an Asian and Oriental way to add acidity.

This is all down to that Ottolenghi fellow, is it? 
Only partly. The vogue for home pickling, brewing and sourdough baking helped, followed by our interest in fermented foods for gut health. Another factor is that acidity makes mocktails more grown-up. Think Nonsuch’s Blood Orange & Bitter Lemon shrub or a recipe for mulled pomegranate juice with sumac in January’s BBC Good Food.

Adventurous home cooks are curious and unafraid to mix and match. A vegan diet isn’t repetitive if you whirl preserved lemons into hummus or sprinkle chaat masala onto almond butter toast.

How do you define sourness?
Sour foods literally make your mouth water. According to Mark Diacono, author of Sour - The magical element that will transform your cooking (Quadrille), relative acidity can be measured on the pH scale; lemon juice is 10 times more acidic than pomegranate. Sourness can’t be neutralised by adding sweetness because sugar has a pH level of 7, but sweetness can be used for balance and contrast and to create flavour explosions.

Tell me more
Over four years ago, Chocolarder in Cornwall sent us a milk chocolate Easter egg filled with sea buckthorn fondant. We still recall the pleasurable clash of sweet and sharp. Chocolarder’s sea buckthorn truffles are sold at Selfridges – an exquisite combination.

The contrast between sour lemons and sweet dates inspired a new preserve from Belazu –Lemon Sweetness.

What’s an unexpected benefit of sour foods?
They work as salt substitutes. As a spokeswoman for the spice retailer, Spice Mountain, explained, customers increasingly ask for no-salt seasonings; their lime and lemon zest powders are bestsellers.

Which sour ingredient gets you particularly excited?
Tamarind. As Glynn Christian advises in Taste: How to Choose the Best Deli Ingredients “(Tamarind is) excellent in all curries. Well worth experimenting with to flavour a sauce for fish, to sharpen a tomato sauce for pasta, in a vegetable soup or as part of an oriental-style salad dressing with soy sauce and chopped, toasted cashew nuts.”

Chef Cyrus Todiwala MBE adds that souring balances the flavour of spices and chilli. His Date & Tamarind Chutney complements Beetroot & Coconut samosas on the Café Spice Namaste menu and will soon be available to independents again after rebranding. 

I’ve always liked tart tastes like pomegranate, blood orange and rhubarb.
Sounds like you’d appreciate Craic Foods’ innovative, northern Irish range of pickled gooseberries, cherries and blackberries. Laura Bradley of Indie Fude, a deli in Comber, County Down which stocks them, said, “I enjoy (these pickled fruits) at home all the time in everything from savoury dishes and salads, to cocktails.”

While the blackberry variant is Indie Fude’s best-seller, Laura says a salad made with the pickled gooseberries, a bright, citrus goat cheese such as St Tola and with the apple and elderflower notes of the pickle in the dressing is “a fine thing indeed”. The pickled cherries make “a brilliant accompaniment to a cheese toastie or pan-fried duck breast.”

The gooseberries variant, which outsells the others, won Grand British Champion at the 2021 Great British Food Awards. It would make a classy accompaniment to any cheeseboard or smoked fish platter.

How can we make the most of the trend?
Consider ingredient bundles – selling a world cuisine cookbook with themed products as a package.

Showcase sour ingredients in takeaway and café dishes. When Trend Watch served a salad of puy lentils, rocket, beetroot, feta and dried sour cherries, it was the sour cherries that provoked curiosity and compliments.

Don’t limit sourdough sales to savoury bakes. Sourdough starter gives sweet bakes like cinnamon raisin bread an addictive tang. 

Will the trend last?
We think it will. Our love of Levantine cuisine shows no sign of abating and interest in Asian and south Asian cuisine is strong.

There’s evidence taste buds are moving away from childish, one-dimensional sweetness. If you don’t believe this, look at the number of producers launching sharper tomato ketchup alternatives.