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

Metrics are like an onion: full of layers.

A simple question to ask can often be complicated to answer. Or we may find that we need to ask a different question. While it'd be lovely to have one simple metric to understand our business the reality is usually a lot more nuanced and interesting than it first seems.

Averages will deceive. Vanity metrics may wow —  by, say, quoting a total user count and conveniently ignoring whether those users are actually paid, active, or leaving. Growth overall can hide declines in other areas or product lines and vice versa. The people on monthly subscriptions may be doing great, while revenue from add-ons may be declining. New users may be signing up in droves while existing users are churning. Mobile traffic may be different from desktop, online sales different from store sales... In practice, it's the hard questions we're usually asking even if we don't know how to ask them.

It pays to carefully consider what you're trying to learn and to understand all aspects of a business before putting faith in the numbers. And it may make sense to start with simpler metrics first.

The metrics onion

Traditionally, stocks have the flavour and gelatinous collagen-y thickness that comes from cooking bones. Broth was cooked not with bones but with the meat itself. While a jus is a sauce made from the pan drippings, usually from a roast. This simple distinction I learned from Thomas Keller.

Now, you can also have vegetable stock, so some other useful distinctions between stock and broth include that, generally, stock is intended to be used in the preparation of another dish rather than eaten directly like broth. As such, you would more likely use whole vegetables in stock to impart the flavour, but still scoop them out afterwards, while a broth would have cut vegetables ready to eat in the broth itself.

Stock, Broth, Jus

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

Before getting started in your kitchen both Thomas Keller and Gordon Ramsay picked out this safety tip to stop your chopping board slipping while cutting. Just lightly wet a piece of kitchen towel or a tea towel and lay it flat between the surface and your chopping board. Hey presto! No slipping while cutting so all your fingers stay intact even with those tricky butternut squash.

Stop chopping board slip

Together, and with the help of a small bowl of water, let’s save millions of perfectly good eggs from being thrown away using the egg float test. Egg shells are very slightly porous. Over time, air seeps into the shell making it lighter than it was, and, when it is old and no longer good to eat, it floats. Hence, the egg float test.

Here's how to test your eggs. Carefully, place an egg into water taking care not to crack it, and watch. If the egg:

…sinks to the bottom and sits on its side, then it’s fresh and good to eat.

…sinks to the bottom but perches on its end, then it’s good to eat, but should be eaten soon — it’s been around long enough to get enough air in it to start lifting it off the bottom.

…floats to the surface, then it’s old and likely no longer good to eat.

Word is that it’s not a good idea to wash eggs well before you plan to use them as it removes a natural membrane coating on them called bloom that protects the eggs from bacteria. So best to only wash them when you’re ready to eat them.

Now, does anyone know of an equivalent test for avocadoes?

The Egg Float Test

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

In the UK and certain temperate latitudes there’s a period where the weather gets warmer and the season late for the winter crops, while the temperatures can still be too low for the Summer crops to get going. This period is known as the Hungry Gap — from late April, through May and a little of early June — as it’s hard to pick enough crops locally at that time of year to live off.

Ellen Warrell at Riverford Organic Farmers explains the Hungry Gap including ways to manage it. For example, did you know that “Trucking tomatoes over from Spain uses just a tenth of the carbon compared with growing them in the UK using heat.”

The Hungry Gap

A cheeseboard is a highlight of the holidays for me. Here are some simple guidelines on how to create a winning one that looks and tastes the part.

I think the key really is the range of textures in the cheese. If you’ve got a hard, semi-hard, and soft cheese you’re onto a good start. If you can add in a crumbly and creamy and make sure you have a range of strengths from mild to mature, stinky or blue you’re onto a winner. Then make it amazing by adding complements from the sweet and salty buckets and don’t forget the crackers and breads.

If you want show off, try to cover a range of cheese shapes, colours and milks such as goats and sheep as well.

Also see, Don’t cut the nose off brie and Compliment, Complement, Freeze stilton.

And because you may find yourself curious about it: origins of Boxing Day.

Compose a cheeseboard

I was taught this originally for backpacking but it really always makes sense once you think about it. Pouring onto a hand keeps dirty hands out of the rest of the snacks in much the same way as a drinking fountain manages to be hygienic by shooting out the water.

Some alternative sides to sharing: compliments are gifts and give gifts others can give. And two more about germs: sneezes and coughs, and the Dracula sneeze.

Pour, don’t dip when sharing snacks.

…when senses interact, in sometimes surprising ways. Some fun examples:

Coffee tastes better when you don’t have a loud coffee machine near you, and it also tastes more intense and less sweet if the mug is white.

In the atmosphere of a pressurised cabin when flying, with decreased humidity and air pressure and significant background noise, things taste less sweet or salty.

If you can’t hear the crunch of, say a Pringles potato chip, then it tastes less fresh.

You might enjoy Nicola Twilley’s super New Yorker article, The Illusion of Taste, which has more of the science and plenty more examples.

Crossmodal perception

So, you finish a packet of crisps, or chips, and scrumple the packet up, but in just keeps uncrumpling and tries to blow away. No longer. This handy little bit of origami creates a neat and tidy little triangle that keeps your crisp packet behaving. Give it a try next time.

HT: Dave Barker taught me this about 20 years ago. I still find it useful.

Tame unruly crisp packets

There always seem to be more than we need in a bag. This is a nice end for them.

Freeze lemons and limes

The classic “use cutlery from the outside-in” still holds, but I realised there’s a little more to it than that. And I learned what a charger is.

Amalgamation of tips from the cookbook I use most, the Joy of Cooking.

Set your table in time-honoured positions.

Sacré bleu! Or camembert for that matter. Share the ripe middle by cutting strips.

Don’t cut the nose off brie

There’s stiff competition for the original and the most authentic British cream teas between Devon and Cornwall and the Southwest of England. And you may have, like me, wondered if when having scones with clotted cream and jam in what order should you put them. However, you can tell each apart by the preference on your scone to go for jam on top of the clotted cream, or under the cream. Cream on top = Cornwall. Jam on top = Devon. If you haven’t had one on location, I recommend you give it a try.

Cream tea: Cornwall vs Devon

Scoville scale: chile heat via capsaicin content

Turns out a bunch of substances have the power to make you sleepy - tryptophan, vitamin B6, calcium, glycine, lactucarium and carbohydrates are some of the major ones. Some even interact with each other for maximum sleepiness. A few common foods with these compounds in good measure include:

turkey, walnuts - tryptophan
tuna, pistachios - vitamin B6
dairy - calcium
chamomile - glycine
lettuce - lactucarium

So an evening turkey or tuna, walnut, cheese and lettuce sandwich with a glass of milk and a side of pistachios or walnuts and you’ll be set for a good night.

Sleepy foods

I’ll understand if this hasn’t been a burning question for you. But I’ve always struggled to identify correctly when one is put in front of me. Turns out, after sleuthing, they do have separating characteristics along, colour, the tightness of skin and the amount of seeds. I had to go 3D, but I think this should allow you to identify the next small orangey thing that you eat.

Mandarin Has seeds, loose skin and is orange

Clementine Seedless, tight skin and orangey-red in colour

Tangerine Has seeds, loose skin and is orangey-red

PS I promise no more mandarin-related sketchplanations in a hurry

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

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

De-seed pomegranates in a bowl of water

Cuts of beef

Boiling point of water vs altitude in ft.

Cooking at altitude

Seems so simple now, but I swear I was in my 20s before I figured this out.

Use serrated knives for foods with a hard outside and soft inside

The most fun and satisfying way to prepare a mango. If you haven’t already, try it.

Hedgehog a mango

Open bananas like a monkey

There are others too. But these are big ones. Curious? Read Metaphors We Live By was a frame-changing easy read for me.

PS Accidentally, mixed my metaphors in the final sketch. The Mind Is A Machine metaphor is so pervasive it’s hard to ‘sketch’ across thinking without it.

Metaphors for ideas

You will have observed this most times there is shared food you can cut. I observed it with trays of brownies that we used to make. Slices start big and get progressively smaller. No one wants to eat the last slice.

A previous boss had a simple solution to this with a maxim he had: You think of one, you get two. A bit excessive, and I don’t advocate it, but it really did work.

The law of diminishing brownies

Roll limes before squeezing and you’ll get more juice

When food seems indestructible you should be suspicious.

If its not good enough for bugs, it’s not good enough for you

Gelato, sorbet and ice-cream

And save a little more time for life. We switched 8 years or so ago and haven’t looked back.

Use crushed garlic and ginger in most of your cooking

Rules of thumb for cooking steak

Trim beans in one cut through the packet

Eat food. Not too much. Mostly plants

Never rush an onion (from Gordon Ramsay), avoid moving chicken if you can, and don’t stir fry too much - best keep stir fries to 1-2 person portions max.

3 Miscellaneous cooking tips

Following on from the original, I love the words: Tofurkey, turducken, and cambozola.

Portemanteau food

Wrap cheese in paper towel to reduce mould

Eating cereals is a subtle interaction of milkiness, crunchiness and time spent soaking. Hat tip.

When combining cereals, layer milk-resistant cereals at the bottom

Among many other sensible suggestions, Michael Pollan recommends avoiding the centre supermarket aisles. It’ll generally keep you on the fresh stuff. Sketchplanation hat tip to Ben Merrick.

Shop healthy

Don’t let the frozen peas escape until you want them to.

Marshal frozen peas and such

Or, buy a rice cooker. You won’t regret it. But still no peeking.

Cook rice like a pro

Buy half-price stilton after Christmas

Get it right and it will fall evenly in the pan and slowly twist it’s way into the water on its own.

Twist your spaghetti

Various informants have since told me that cutting horizontally first helps keep it together better as you’re cutting, and that cutting this way first helps keep the tears away longer. I’d probably vote ease of cutting and reverse the order here.

Cut an onion into teeny pieces

For something so delicious Thai curries are really remarkably fast and easy to cook yourself. Try it.

Cook delicious, yummy, Thai curry

Make Vietnamese coffee

My dad often says my mum won’t survive when he’s gone as she won’t be able to open any jars for food. Maybe this’ll help. Warming up jar lids has saved me on multiple occasions.

Fourth Try: Put folded dish cloth on counter and whack the edge of the lid against it. Boom. (courtesy @MrRobBell)

Remove troublesome lids

Learned from the lovely people at the Suntouched Inn, Napier, South Africa.

Make a Wayne’s World pizza

Your handy reference for how to poach an egg in the microwave. In just a minute with a mug, a microwave, and a little water, a perfectly serviceable poached egg can be yours.

Sketchplanations tagged with food