Here's how you dunk your biscuits like a pro - according to scientists

Scientists have revealed the perfect formula for dunking biscuits – discovering Rich Tea, Hobnobs and Digestives should be submerged for less than ONE second.

Dr Helen Pilcher, who has a PhD in stem cell biology, conducted an experiment to discover the optimal time to submerge biscuits in hot drinks – and at what point they reach the ‘dunking danger zone’.

She found the average biscuit should absorb 20 per cent of its original weight in liquid for the optimal dunk experience.

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Milk Chocolate Digestives and Hobnobs can be dunked for just over three seconds to reach this point, while Penguin bars should remain in the hot drink for a whopping six and a half seconds. 

However, it takes a mere five and seven seconds respectively for Fruit Shortcakes and Ginger Nuts to reach the danger zone – which is when they are at risk of breaking.

But Dr Pilcher, who has been appointed by McVitie’s as their ‘chief dunking officer’ (CDO) to carry out the study, found a Chocolate Caramel Digestive can withstand an astonishing 40 seconds of plunging time before being in trouble of being lost to the depths of a cuppa.

Each of the biscuits involved in the study were dunked vertically, to its mid-point, in a mug of freshly prepared tea – with milk, no sugar – and maintained at a temperature of 60 to 65oC.

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Taking on the role of CDO, Dr Pilcher is aiming to make biscuit and beverage related woes a thing of the past by taking the guesswork out of the dunk.

There's an actual scientific dunking formula for your favourite biccyThere's an actual scientific dunking formula for your favourite biccy
There's an actual scientific dunking formula for your favourite biccy | PinPep

The perfect dunking experience

The appointment of the new role comes after a poll commissioned by biscuit maker revealed 83 snacks per dunker are lost on average every year to depths of a mug due to poor dunking techniques.

As a result, 43 per cent have even become anxious about losing their sweet treats when dipping – with 29 per cent confessing they need to perfect their dunking technique.

Dr Helen Pilcher said: “The natural porosity of a biscuit makes it an ideal snack to be dipped into a drink and soak up all the deliciousness. However, Brits are still susceptible to over-dunking their biscuits – which is why we have identified the Optimum Dunking Time and the Dunking Danger Zone.

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“Each biscuit is unique in texture, structure, flavour and size, and all these factors affect its dunkability. Respect the Dunking Danger Zone, and we can save the nation from future dunking disasters.”

It also emerged from the poll of 2,000 biscuit dunkers that Digestives are the favourite treat to submerge, closely followed by the Chocolate Digestive and Rich Tea.

Tea, coffee, and hot chocolate are the most popular beverages to dunk in – though some also dunk in cold or warm milk, milkshakes and even orange juice. Over half (53 per cent) of those polled via OnePoll say they dunk their biscuits because they like the flavour, and 50 per cent like the change in texture.

Generation X dunk the most biscuits, with one third saying they dunk ‘often’, closely followed by Millennials (29 per cent) and Baby Boomers (29 per cent).

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James King from McVitie’s UK & Ireland said: “We were shocked following the results of our survey to discover just how many biscuits are being lost to dodgy dunking each week. As the baker of the nation’s true original biscuits, we feel we have a duty to help, which is why we’ve appointed a chief dunking officer to save the Great British public from dunking debacles and achieve the perfect dunk, every time.”


Biscuit / Optimal Dunking Time (seconds) / Dunking Danger Zone (seconds)

  1. Ginger Nuts / 0.3 / 7.3
  2. Fruit Shortcake / 0.3 / 5.3
  3. Digestive / 0.4 / 11.2
  4. Hobnobs / 0.5 / 12.5
  5. Rich Tea / 0.6 / 8.8
  6. Jaffa Cakes / 0.6 / 9.2
  7. Milk Chocolate Digestive / 3.6 / 12.0
  8. Milk Chocolate Hobnobs / 3.7 / 19.5
  9. Chocolate Caramel Digestive / 5.0 / 40.1
  10. Penguin / 6.5 / 540.0
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