How SpreadTHAT! Works: The Science Behind the Self-Heating Butter Knife
Cold butter tears bread. It clumps in the middle, leaves the edges bare, and the usual fixes all have drawbacks. Leaving butter on the bench is a food safety issue. Microwaving it is too easy to get wrong. A hot knife under the tap works once and then goes cold again.
SpreadTHAT! takes a different approach, using physics instead of electricity.
What Is SpreadTHAT!?
SpreadTHAT! is a self-heating butter knife made by Dutch design company THAT! Inventions. Inside the blade is a superconducting core, a sealed chamber containing a thermal liquid that activates at body temperature.
When you hold the handle, warmth from your hand conducts through into the superconducting core. The thermal liquid changes phase and transfers that heat rapidly along the full length of the blade, warming the edge just enough to glide through cold butter straight from the fridge.
No electricity, no batteries, no preheating required.
Why Does It Actually Work?
Standard metal conducts heat slowly. The superconducting core in SpreadTHAT! transfers heat roughly 10,000 times more efficiently than a standard steel knife of the same size. The blade warms within seconds of being picked up and stays warm throughout use.
The serrated edge shaves fine butter curls from the block, which melt against the warm blade and spread smoothly. It works on butter, peanut butter, cream cheese, chocolate spreads, and similar.
The Awards
SpreadTHAT! won the iF Product Design Award, one of the most recognised design honours in the world with over 11,000 entries per year. It also won the Houseware Innovation Award. Both recognised the engineering behind the product, not just the appearance.
Who Uses It
It's useful for anyone who keeps butter in the fridge and eats anything that needs spreading. People who bake find it particularly handy for getting butter to the right consistency without waiting. Households with young children appreciate that there's no heat source involved beyond body temperature.
Frequently Asked Questions
Does SpreadTHAT! need batteries or charging? No. It runs entirely on body heat with no electricity, batteries, or charging required.
Will it work on butter straight from the fridge? Yes, that's what it's designed for.
Does it work on other spreads? Yes. Peanut butter, cream cheese, chocolate spreads, and other thick spreads all work well.
How do I clean it? Hand wash with warm soapy water. Not dishwasher safe.
Where can I buy SpreadTHAT! in New Zealand? Exclusively from Luxify. We are the only authorised distributor of THAT! Inventions products in New Zealand and Australia.
How long does delivery take in NZ? Most orders arrive within 2 to 5 business days.