The flavour of Zerbinati’s Watermelon Kombucha has drawn praise from Saturday Kitchen, our customers, and other kombucha companies. What makes it so special?

It starts with a single grower and a single genus of fruit: Oscar Zerbinati and the Sentinel Watermelon.

It ends with intense, rich watermelon juice, bold enough to stand up to our raw, traditional kombucha.

To learn about the magic that happens in the middle, we travelled to Oscar's farm in Italy's fertile Po Valley to see it first hand.

A land fed by flood

Oscar’s land lies on the floodplain of the River Po. Once a lagoon for the river’s overflow, the soil is packed with complex minerals and organic matter.

It's extraordinarily fertile ground, a place of abundance. Even in the heavy heat of late June 2026, the drive to his plot was lush green in every direction. For thousands of years, this area has been the breadbasket of Italy.

But where most crops are grown for sheer yield, the Zerbinati farm puts quality and flavour first. On his farm it's green in every direction too, but the watermelons are few and far between. He wants a large plant's full attention to centre on one perfect watermelon.

Drawing from a lineage of flavour

For three generations, the Zerbinati family has prioritised flavour over yield. While many neighbouring farms switched to intensive, high-yield varieties, the Zerbinati's doubled down on time-honoured practices even when it meant harvesting fewer fruits.

That dedication has earned them an outstanding reputation. They're one of the most celebrated growers in the region.

Directing nature’s energy

Clay soils hold nutrients but also trap water. Watermelons are natural sponges – given the chance, they will soak up as much water as possible, diluting their flavour.

On the clay-rich soils of his farm in Sermide, Oscar shields the plants from rain and raises the best fruits onto mounds so excess water drains away.

Smaller fruits are removed, allowing each plant to channel its energy into one. The result is very large watermelons, up to 18kg, with punchy sweetness and dense flesh. It’s an approach that makes the Sentinel the perfect match for our unfiltered kombucha.

Thinning, training and timing

Sentinel is already a low-yielding, thin-skinned variety, so most growers avoid it. Oscar makes it his own.

He thins his melons to less than half the number of fruits that conventional growers allow. Vines are trained on raised beds and protected by sheeting; young shoots are pinched off so that the plant can channel nutrients into a single fruit.

Timing is critical. With decades of experience, Oscar and his family know when a melon is at peak sweetness. He uses a colour-coded ribbon system to tag each fruit according to when it was pollinated, allowing him to track exactly how long it has ripened on the vine.

A spot of sunscreen

The Mantuan sun can scorch watermelons, so Oscar even applies a chalk and gravel-based sunscreen to the fruits and leaves. This chalky coating shields the melons from sunburn and allows them to ripen slowly.

After harvesting, he packs each fruit into a crate lined with straw so that the thin skins don’t bruise during transport. Painstaking handling is required to preserve the melons’ integrity from the field to your glass.

Why Sentinel?

The Sentinel is a heritage variety introduced around 50 years ago. Unlike modern mass-produced watermelons, it grows slowly and has a thin rind.

The long gestation period helps the melon to draw in the clay's rich minerals, building texture and deepening flavour. 

Watermelons aren’t usually this sweet, this dense – Zerbinati’s Sentinels are.

The journey from farm to kombucha

For our limited-edition Zerbinati’s Watermelon Kombucha, Natoora deliver Oscar’s finest fruit at the height of the season and press the juice at their London site. Working with fruit at peak ripeness means every drop is sweet, fragrant and true to the melon’s character.

We blend that fresh juice with our raw, unfiltered kombucha, the watermelon’s clean sweetness balancing the tang and depth of our slow ferment.

It’s a mid-summer favourite. It’s here for a limited time only – and with 10p from every bottle going to Natoora’s Farm Fund to support the next generation of sustainable farmers, now’s the moment to enjoy it.

Bottled at the height of seasonality

The mineral-rich soils of the Po valley, the careful pruning and water management, the sunshine filtered through chalky sunscreen – all of this labour yields watermelons unlike those you'll find in the supermarket.

With so much love and attention going into each Sentinel Watermelon, it's our responsibility to give the same care to the final kombucha. With Zerbinati's Watermelon Kombucha, we think we've been pretty successful.

When you sip our kombucha, you’re drinking the work of a family that has chosen flavour over yield for three generations.