Simple Hot Lunches to Carry in a Flask

There is a particular sort of misery that comes from eating a damp cheese sandwich on a wind-scoured ridge in February. Your hands are numb, the view is grey, and the sandwich has somehow absorbed the cold. Ten minutes later you are still shivering. A flask of something hot changes the entire day. It is not just the calories — it is the ritual of stopping, unscrewing the lid, and letting the steam warm your face before the first spoonful has even reached your mouth.

The trick is choosing food that survives being sloshed about in a rucksack for four hours, and a flask that lets you get at it properly. Here is what works.

Get the Right Flask First

A narrow-necked vacuum flask is brilliant for tea and useless for stew. What you want is a wide-mouth food flask, usually 500ml to 750ml, with a screw-on lid that doubles as a bowl or cup.

• Wide mouth, wide lid: if you cannot fit a dessert spoon in easily, you will be eating your lunch in frustrating little dribbles.
• Pre-heat it: fill with boiling water, screw the lid on, and leave it for five minutes while you finish packing. Tip the water out, then add your hot food. This single step can add two hours of heat.
• Fill it to the brim: trapped air is what cools food fastest. Leave no headspace if you can help it.
• A long-handled spoon: a standard teaspoon will leave you scraping the bottom with cold fingers. A spork or a proper camping spoon is worth its weight.
• A cloth or small tea towel: wrap it round the flask in your pack. It stops rattling, insulates a little more, and mops up the inevitable spill down your waterproofs.

Test your flask at home before you trust it on a summit. Fill it with hot soup at seven in the morning, leave it on the counter, and open it at two. If it is merely lukewarm, it is not coming with you.

Thick Soups That Travel Well

Thin, watery soup is a poor traveller — it sloshes, it cools quickly, and it never feels like a meal. Go for something with body.

• Lentil and bacon: thick, salty, and filling. Blend part of it if you want it smoother, but leave some texture.
• Split pea and ham: almost porridge-like when made properly, which is exactly the point.
• Butternut squash and red lentil: naturally sweet and thick, and it takes well to a pinch of chilli or smoked paprika.
• Potato and leek: cheap, comforting, and it thickens beautifully if you let it cool slightly before blending.

Keep the consistency like double cream rather than milk. If it pours, it will be cold by the time you reach the top of the climb. A swirl of cream or a knob of butter stirred in just before you decant it into the flask adds richness and helps it hold heat.

Stews and Casseroles for Long Days

A stew is really the ideal flask food because it is designed to be reheated and it improves overnight. Make it the evening before, cool it quickly, and fridge it. In the morning, reheat it thoroughly on the hob, then pour it straight into the pre-heated flask.

Chunky is good, but keep the pieces spoon-sized. A whole chicken thigh is awkward to eat standing up in a gale. Cut meat and root vegetables into mouthfuls. Good options include:

• Beef and ale stew with carrot and swede — rich and warming, though it stains, so mind your lid.
• Sausage and bean casserole — a tin of butter beans or haricots thickens the gravy and adds bulk.
• Chicken, chorizo and chickpea — smoky and satisfying, and it travels brilliantly.

Watch the salt if you are walking hard. A very salty stew will leave you thirsty, and if your water is frozen solid in the bottle, that is a problem. Go easy on the stock cubes.

Curry and Dahl: The Real Winner

For my money, a thick curry is the best hot flask lunch there is. It is intensely flavoured, which is exactly what you want when your taste buds have gone numb, and it stays hot for hours because of its density.

• Chicken or chickpea curry: a tomato-and-onion base, plenty of spice, and enough sauce to coat a spoon.
• Dahl: red lentils cook down into a thick, spoonable potage. Add coconut milk and it becomes silky.
• Keema: minced lamb or beef with peas, heavily spiced, holds its heat superbly.

Take a couple of chapatis or a small naan wrapped in foil in your pack. Bread is the perfect scoop and it turns a flask of curry into a genuine hot meal rather than a snack. If you are carrying a small insulated pouch, it will keep the bread from going icy.

Wild Camping and Overnight Trips

When you are camping out, the flask earns its place twice over. Fill it at teatime with a hot stew, seal it, and it will still be warm at nine in the evening when you are sitting in your sleeping bag listening to the wind. It saves you lighting the stove again in the dark.

• Boil once, eat twice: make a generous batch of stew at dinner and decant the surplus into the flask for the morning. Breakfast in bed, camping style.
• Oatmeal works too: thick porridge with raisins and a spoon of jam, poured into the flask at night, is warm and ready at dawn.
• Mind the weight: a full 750ml flask is roughly a kilo. On a long backpacking day, that is a real cost, so leave the spare water bottle behind to balance it out.

Do not forget the small things. A cloth for spills, a bag to put the dirty spoon in, and a spare lid seal if your flask is elderly. Few things are worse than discovering at the summit that your lunch has leaked into your spare socks.

Pack the flask, pre-heat it properly, and choose something thick enough to stand up to the journey. Cold days out are always better with a hot spoonful in the middle of them.