Scientists reveal best formula for dunking biscuits in tea & coffee – and how long each should be submerged for
BISCUIT maker McVitie's has hired its first-ever Chief Dunking Officer, who has revealed exactly how long you should dip biscuits before it disintegrates into mush.
There's nothing worse than losing a biscuit to a cuppa, or a sediment and debris-rich brew.
As the UK's very first Chief Dunking Officer, Dr Helen Pilcher's first port of call is to put a stop to a gritty "over dunking" experience by explaining the science behind the 'perfect tea dunk'.
"The natural porosity of a biscuit makes it an ideal snack to be dipped into a drink and soak up all the deliciousness," Dr Pilcher explained.
"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 for a range of McVitie’s classics."
McVitie's is the retailer behind some of the nation's beloved biscuits: Digestives, Hobnobs, Gingernuts, Fruit Shortcakes, Rich Tea Biscuits, Jaffa Cakes and Penguins.
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Each biscuit has a unique texture, structure, flavour and size to the rest, which ultimately affects its so-called "dunkability".
According to Dr Pilcher's 'Biscuit Immersion' study, the 'perfect dunk' is when a biscuit absorbs just enough liquid to give it added softness and flavour, but not so much that it becomes mushy.
When a biscuit is about to enter the dunking danger zone, it exhibits at least one of three diagnostic warning signs: disintegration, bending and the appearance of a fault line or crack.
“For the optimal dunking experience, it is crucial not to dunk beyond the dunking danger zone,” advises Dr Pilcher.
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“It’s utter dunking madness to enter this structurally dangerous territory.”
These 10 McVitie’s biscuits were put to the test: Digestives, Milk Chocolate Digestives, Milk Chocolate Caramel Digestives, Hobnobs, Milk Chocolate Hobnobs, Gingernuts, Fruit Shortcakes, Rich Tea Biscuits, Jaffa Cakes and Penguins.
Each biscuit was dunked vertically, to its mid-point, in a mug of freshly prepared tea (milk, no sugar), maintained at a temperature of 60 to 65C.
The study found the gingernut biscuit, for example, requires just 0.30 seconds in a hot, milky brew, to achieve dunking perfection.
While the chocolate hobnob requires 3.7 seconds.
The complete biscuit breakdown:
| McVitie’s Biscuit | Optimal Dunking Time(seconds) | Dunking Danger Zone(seconds) | CDO’s Suggested Beverage Pairing |
| Ginger Nuts | 0.3 | 7.3 | “The Ginger Nut is the British Amaretti biscuit and just like its Italian counterpart, this lightly spiced biscuit is ideally complemented with milky coffee.” |
| Fruit Shortcake | 0.3 | 5.3 | “Chai latte - this aromatic brew, with sweet and spicy overtures, is the perfect companion for this understated biscuit classic.” |
| Digestive | 0.4 | 11.2 | “A sweet tea pairs perfectly with the almost savoury flavour of the Digestive.” |
| Hobnobs | 0.5 | 12.5 | "A tasty blank canvas, so versatile it will enhance any beverage you choose. A true dunking all-rounder.” |
| Rich Tea | 0.6 | 8.8 | “Taken with builders tea this is a British institution, on par with strawberries and cream at Wimbledon.” |
| Jaffa Cakes | 0.6 | 9.2 | “The sweet orange centre of Jaffa Cakes are perfectly offset by the bitter notes of a fresh brewed black coffee.” |
| Milk Chocolate Digestive | 3.6 | 12.0 | “Taken with Earl Grey tea – the chocolate mixes beautifully with the bergamot, to make a liquid chocolate orange flavour.” |
| Milk Chocolate Hobnobs | 3.7 | 19.5 | “Milk (warm or cold) is ideal - the creaminess of the milk pairs perfectly with the oatiness of the biscuit.” |
| Chocolate Caramel Digestive | 5.0 | 40.1 | “Cappuccino - known for its cocoa powder topping, why not intensify the experience with an extra hit of chocolatey sweetness.” |
| Penguin | 6.5 | 540.0 | “While I personally recommend a Penguin should be enjoyed undunked, a hot chocolate triggers a double-dose of chocolatey delight.” |
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