Add butter to lighten your mash? 2g bicarb beats 50g butter per 1kg spuds: you waste cash daily

Autumn plates call for comfort, yet comfort often hides costly habits. Many kitchens cling to butter for lift, and pay twice.

Your saucepan can do better. A tiny change during boiling turns mash from dense to cloud-like, trims fat, and saves money.

Why butter can weigh down your mash

Butter brings flavour and gloss. It also adds fat that coats starch granules. That coating stops steam from puffing the mash. The result feels rich but heavy. Add more butter and the mash packs tighter. Add more mixing and the mash turns gluey. Texture suffers before taste improves.

For lightness, you need starch to swell and separate, not clamp together. Heat, pH, and method decide that outcome. Butter affects taste more than structure.

For lift, work on the potatoes in the pot, not on the butter at the end.

The pinch that lifts: how bicarbonate of soda changes the game

Bicarbonate of soda nudges the cooking water towards alkaline. That tiny shift loosens the pectin in cell walls. Cells separate cleanly. Starch disperses evenly. Your mash aerates under the masher, not the mixer. You gain volume without extra dairy.

Use precise amounts. Add 1–2 grams of bicarbonate per 1 kilogram of potatoes. Sprinkle it into the boiling water once the potatoes start to soften. Stir once. Drain well. Then mash.

Add 2g bicarbonate per 1kg potatoes to the boiling water. Drain, then mash. Do not exceed the pinch.

What the chemistry does for texture

Alkaline water weakens pectin bridges between potato cells. Cells break apart without tearing. Less torn cells means less free starch paste. Less paste means less stickiness. Air pockets stay trapped as you mash. The mouthfeel turns light, not gummy.

Step-by-step for mash with lift

• Choose 1 kg floury potatoes, such as Maris Piper, King Edward, or Desiree.
• Peel and cut into even chunks, about 4 cm. Rinse off surface starch.
• Cover with cold water by 3 cm. Add 10 g salt per litre.
• Bring to a gentle boil. Simmer until just tender at the centre.
• Add 1–2 g bicarbonate to the pot. Simmer 60 seconds more.
• Drain thoroughly. Return potatoes to the hot pan to steam off moisture.
• Mash by hand with a ricer or masher. Avoid a blender or food processor.
• Warm 250–300 ml milk or unsweetened oat drink. Add in small splashes.
• Season with salt and white pepper. Add 10–20 g butter only if you want extra flavour.

Never blitz mash in a food processor. You break cells to paste and lose the airy texture you just earned.

How much is too much: taste, sodium, and safety

Too much bicarbonate gives a soapy taste. It also lifts sodium. Stick to 1–2 g per kilogram. Measure with a 1/4 teaspoon levelled, not a heaped spoon. If you overshoot, add a squeeze of lemon to the liquid you fold in. Acid rebalances the pH and tames the flavour.

Anyone watching sodium can still use the method. Cut the added salt in the water by half. Bicarb boosts perceived softness, so you need less salt to feel seasoned.

Does it save money and calories?

Butter costs more than bicarbonate. Bicarb costs pennies per pinch. Butter at 50 g per batch adds over 360 kcal and around 25 g saturated fat. The bicarb method needs little or no extra butter to feel indulgent. That trims energy and weekly spend without dulling flavour.

Choosing the right potato and kit

Best varieties for fluff

Maris Piper gives a classic British mash with lift. King Edward goes floury and aromatic. Desiree sits between fluffy and creamy. Waxy types, like Charlotte, stay firm and can turn tacky when mashed.

The tools that help

• Ricer: produces uniform grains that drink warm liquid evenly.
• Hand masher: keeps some texture and protects against glue.
• Fine sieve: for silkier mash, push riced potato through once.

Flavour variants that stay light

You can fold in flavour without weight. Warm liquids carry aromatics into the mash. Keep additions modest to protect the lift.

• Milk infusions: simmer bay leaf, garlic, or thyme in milk, then strain.
• Herb oils: swirl in a teaspoon of chive or parsley oil at the end.
• Dairy swaps: use warmed oat or almond drink for a clean finish.
• Tangy lift: stir in 2 tablespoons of plain yoghurt or soft goat’s cheese.
• Spice: a pinch of nutmeg or white pepper brightens without heat.

Common mistakes and quick fixes

Watery mash

Cause: under-drained potatoes. Fix: return drained potatoes to low heat for two minutes, shaking to steam off moisture.

Soapy note

Cause: too much bicarb. Fix: add a small splash of warm milk with a few drops of lemon juice to rebalance.

Gluey texture

Cause: aggressive mixing. Fix: stop mixing; fold in a little more warm liquid and flake in a boiled potato if available.

Serving ideas that respect the texture

Pair airy mash with slow-braised beef shin, roasted carrots, or garlicky mushrooms. Spoon into a shepherd’s pie and bake until just bronzed. For fish, whisk in a tablespoon of olive oil and lemon zest to match cod or haddock.

Numbers you can use tonight

For every kilogram of potatoes, remember 2–10–300: 2 g bicarb, 10 g salt per litre, 300 ml warm liquid.

That trio gives enough seasoning, the right chemistry, and the moisture needed for a billowy finish. Adjust liquid by 25–50 ml if your potatoes seem extra dry.

Beyond potatoes: where the trick still helps

The same pinch helps celeriac or parsnip purée. Root veg hold firm cell walls. A whisper of bicarb softens them faster. Use half the amount you’d use for potatoes. Taste as you go. Keep the heat gentle to protect flavour.

Extra guidance for keen cooks

Want a restaurant-style sheen without heaviness? Mount the finished mash with 10 g cold butter and a teaspoon of neutral oil. The oil stabilises the emulsion so a tiny amount of butter stretches further. Serve at once. Holding mash on heat for long periods toughens it as starch retrogrades.

Cooking for a crowd? Boil and rice the potatoes a few hours ahead. Spread the riced potato on a tray and chill. At service, reheat with hot milk in a pan, folding gently. The structure stays light if you avoid aggressive stirring.