The tomato test, or tomato slicing test, is a handy way to see if your knives could do with sharpening. The idea is that a properly sharpened blade should slice through the taut skin of a tomato with minimal pressure.

Somewhat counterintuitively, most cooks seem to agree that sharp knives reduce the risk of accidents as you don't have to push down as hard as with blunt knives.

To do the tomato slicing test: Place a tomato on a board and gently run the knife over the top surface. A sharp blade will glide through the tomato skin, cutting it precisely all the way down. You shouldn't need to apply any pressure if the knife has weight. If you need to push down to pierce the skin, it could be time to sharpen.

Cutting the top off the tomato first allows it to sit stably on its end, so you don't have to hold it.

Alternatively, you could use a serrated knife which is handy for foods with a hard outside and a soft inside.

The sharper the knife, the less mess you'll make and the easier you can ghost cook.

The tomato test

The rule of 7 is an idea in marketing that it can take hearing a message 7 times before we might take action.

Apparently the rule is from early movie marketing and while I don't know if I'd rely on the number it certainly seems a sensible idea to keep in mind that you can't expect people to take action the first time they hear your message — if you're trying to get people to try something new be it buying food, downloading your app, watching a movie, or a choosing an electric car, it takes a while and repeated exposure before you can expect it to pay off.

I can't remember where I heard it, but some advice I keep in mind when communicating is that by the time you're tired of saying it, others are just starting to hear it. It's not a bad thing to repeat your main message.

I learned about the Rule of 7 from the recent book Human Powered by Trenton Moss.

When putting an apple in the adverts on this sketch I was reminded that so often it's the things in the supermarket that are most healthy for us that don't get anyone shouting about them at all.

The rule of 7

If you like pomegranate but are put off by the prospect of the effort of pulling out each individual seed and spraying pomegranate juice across the kitchen, then this is a fun and handy tip.

a bowl of water helps stop spraying when pulling them apart and naturally separates the light fluffy pith from the seeds, and 

whacking them on the back with a spoon is a surprisingly effective and fun way of making the seeds shoot out.

Deseed a pomegranate

That classic thing: tomatoes are really a fruit — well, a whole lot of other vegetables are technically fruit too. I do find this way of thinking of it helpful:

Fruit — ovaries developed from the flowering parts containing seeds. They’re basically what grows where the flower was.

Vegetable — other edible parts of a plant. So basically, anything else, with a handy list being: leaves, roots, stems and flowers.

So this makes tons of other common vegetables actually fruit, including peas, avocadoes, cucumbers, eggplants, bell peppers and more. And corn and raspberries are still rather complicated.

Some other fruit and veg sketchplanations:

what’s the difference between mandarins, clementines, satsumas and tangerines?

Fruit vs vegetable

The fluff floats to the top and the seeds will sink to the bottom. And no squirting. HT Alex Maiereanu

Sketchplanations tagged with fruit