Tomatoes come into their own in summer, but which supermarket offerings are super sweet, firm and juicy and which are forgettably flavourless?

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From brick-red to intense maroon, the tomatoes in this test varied greatly, with the most flavourful ones often also being the richest in tone. I measured the sugar content using a Brix refractometer, and the tomatoes’ sweetness also varied hugely, from a sometimes bland and watery Brix score of four (each point represents 1% sucrose in the juice by mass) to a satisfyingly sweet seven.

I also scored the tomatoes on overall flavour. The sweetness of the best examples is well balanced, with a refreshing acidity, a fresh and potent tomato leaf aroma, and a complex umami profile that provides an explosion of flavour in the mouth. I also awarded points for value for money, provenance, transparency and growing methods – though, disappointingly, an organic certification did not necessarily equal the flavour I’ve come to expect.

Because tomatoes are a seasonal crop, flavour and availability will change over the summer. Depending on when you buy them, you may find different varieties in shops from those tested here.

Even ripe-looking tomatoes will benefit from being left on the countertop for a few days, so they ripen further and improve in flavour. Never keep them in the fridge, because that adversely affects their texture and taste.

A medium-size, wonderfully deep maroon-coloured variety called Viola Cocktail, grown by Isle of Wight Tomatoes. Proof that delicious tomatoes can be grown in the UK. Quite sweet (Brix score of seven) with a low acidity and incredible, rounded umami flavour.

A large, round, deep scarlet-red Ronvine tomato grown in Essex with Soil Association organic certification. A strong green-tomato vine aroma and noticeably fresh stalks. A firm, fleshy classic sandwich tomato with a subtle sweetness (four on the Brix scale) and a little acidity. Freshness, organic status and price make this my best bargain.

A medium-large round tomato with an intense orange-red skin, and grown in the UK. Medium sweet – Brix score of five – with a low acidity and rich umami flavour. One of the better-value entries.

Medium-sized, orange-red Saint Anna tomatoes grown in the Netherlands. Medium sweet, these have a Brix score of five, with a simple flavour and a wonderfully lush, tomato leaf aroma.

A small- to medium-size juicy, brick-red tomato called Annico Cove, grown at Thanet Earth in Kent, the UK’s largest greenhouse. A mild flavour, but relatively sweet, with a Brix score of six.

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A large, round variety called Roterno, grown in Scotland. A mild sweetness, with a Brix score of four and a flat, one-dimensional flavour. A very standard sandwich tomato.

A medium-size, round Sweeterno tomato grown in Hertfordshire. A traditional sandwich tomato with a subtly mild sweetness and Brix score of five, and very firm flesh and skin.

A medium-size, glossy, round, scarlet-red tomato called P1, grown in the Netherlands. Firm flesh but without much substance; watery and mild-flavoured, too, with some sweetness – Brix score of five.

A medium-size, round organic Spanish tomato with gold-flecked skin. Firm but flavourless, with a low Brix score of four. Packaged in a tray with compostable film.

A large, round, orangey-red tomato of unknown variety grown in Sicily. Disappointing, watery and mild in flavour, with a subtle but balanced sweetness, and a Brix score of five. Packed in a cardboard box in compostable film.

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