Whipping yarns

In my researches for my kitchen science pieces, I kept finding articles on the internet explaining how to whip cream. Was it such an issue, I wondered? The advice always stressed it was important to keep the cream cold, preferably by chilling the bowl and even the whisk. This would keep cream stiff, whipped and stable. Some even went so far as to say that cream wouldn’t whip if even slightly warm. The explanation given was that the action of whipping cream into a foam generates heat. Fats become more liquid when warmed and therefore the foam becomes more unstable. Fair enough, I thought, that makes sense and I was almost willing to leave it at that. If the likes of cookery science guru Harold McGee, meticulously researched website Cooks Illustrated and many more, insisted on whipping cream in a walk-in freezer (OK, I exaggerate a little), who was I to disagree?

It wouldn't be a proper trifle without a fluffy
cloud of whipped cream on top

It was when an office discussion turned to Easter trifles (fruit jelly or a lovely rhubarb and ginger) that I decided to give the delicious. food team the benefit of my recent learning. However, my prideful bubble was punctured by food editor Lizzie saying. “Actually, when it’s really cold cream takes a lot longer to whip. When we do a shoot, I always let it warm up a little – makes it much quicker.” It sounded like heresy but, despite me waving copies of respected tomes under her nose, Kamenetzky was adamant. “I’ve done it hundreds of times at photo shoots.”

Er, how could that be? Only one thing for it. I put my lab coat on, gathered up my digital thermometer and four sets of bowls, whisks and tubs of double cream (it’s what we usually use). One set was chilled to 4°C, another was left to until it was 10°C, another was left to until it was 15°C, and the last was left to warm to room temperature: 20°C.

The batch of chilled cream took an arm-numbing 120 seconds (ok, I’m a geek not a gym jock) to whisk to firm peaks. The second took 30 seconds, the third took 16 seconds and the room temperature cream came together in about 15 seconds or possibly less.

That wasn’t quite what I expected. However, the textures of the whipped creams were all very different, ranging from glossy, white and voluminous like shaving foam at the cold end of the spectrum, to a smaller, buttery and damp splodge for the warmer cream.

Left to right: Cream whipped at 4°C and cream whipped at 10°C (the colours weren't so obviously different, there's a lighting issue)

Left to right: Cream whipped at 15°C and 20°C

Could I explain it? Why had the commentators got it so wrong? I think it can only come down to the fact that most of the commentators were American: double cream in the UK is so high in fat (around 50%) that there are enough fat globules to form a stable foam at higher temperatures than heavy cream (over 36% fat) – what they call double cream in the US. 

Plus, you could argue they were talking about the "best" way to whip cream and were probably using an electric whisk. I do think the cold whipped cream looked the prettiest. However, the cream whipped at 10°C looked fine and would have been great as a filling for cakes and so on as it had more body than the foamy cold-whipped cream. The other two were a little on the wet side.

So what are my conclusions? Well, you don’t need to worry so much about chilling the cream beforehand – it comes down to what you want to do with your whipped cream or what equipment you’re using. If you’re using an electric hand whisk or food processor, you should chill your cream a little as it will be easier to avoid over-whipping it, turning it into butter, often a risk with electric whisks. If you’re whipping by hand – and many claim it gives a better texture – you might find it less tiring if you let the cream warm up a few degrees from the fridge. For what it's worth, I think cream whipped at this temperature would make a better, more robust filling for cakes such as this rather nice lemon coconut sponge.

THE SCIENCE BIT: What is whipped cream?

Put simply, cream is made up of water, proteins and fat. The action of the wires of the whisk cutting through the cream introduces air bubbles and roughs up the fat globules, stripping patches of protective coating from them. As fat and water don’t mix well, the raw patches of fat try to avoid the water by sticking to other raw patches of fat on adjacent fat globules or positioning themselves away from the water facing the air of a bubble. In this way a mesh of fat globules builds up around the air bubbles, linking to to other meshes and trapping the water and proteins in-between, turning what was a liquid into virtually a solid – the whipped cream.