Do you like to dunk a biscuit in a hot drink or a glass of milk? Do you find some biscuits are better for dunking than others? Personally, I’m a big fan of the chocolate digestive to dunk. The combination of melted chocolate and soft biscuit is the best!
What makes a good dunking biscuit? Do you like to dunk a biscuit more than once, or do you prefer one dunk to give the perfect melty texture?
We designed an investigation to find out which type of biscuit is best to dunk. Everyone can probably agree that a biscuit breaking and landing in the drink is never a good thing, so we placed six different biscuits in hot water and timed how long each took to collapse.
We chose to test typically British biscuits, but you can use any type you want.
Biscuit dunking science investigation
You’ll need
Timer
Transparent cups
Different types of biscuits
Warm water
Measuring cup
Instructions
Carefully pour the same amount of warm water into each cup.
Place a biscuit in each cup and start the timer. If the biscuits are too wide, snap them in half. Each biscuit should touch the bottom of the cup.
Start the timer and record how long it takes for each biscuit to collapse.
Another way to do this is to place each biscuit on a separate plate and drop the same amount of water onto each. Weigh the biscuit before adding water, and again five minutes after adding water. The biscuit that absorbs the most water will be the one most likely to fall into your drink.
I’ve created a biscuit dunking challenge investigation sheet to record results and write up the investigation.
Which is the best biscuit to dunk?
We found the shortbread biscuit could be dunked the most number of times without breaking and was the last biscuit to collapse in the cup of water test.
So, if you want a sturdy biscuit that can be dunked more than once, choose a shortbread-style biscuit.
Extension tasks
Repeat the activity using cold water and compare the times with hot water.
Dunk the biscuits in a warm cup of tea to find out if they behave differently than in cold water?
If you enjoyed this activity, take a look at my other delicious edible experiments!
Last Updated on June 9, 2025 by Emma Vanstone
