How to make dirty soda creams and foams

A flavoured cream or a foam is what goes on top of a dirty soda, a coffee or a shake, and there are four ways to make one: whisk a cream, shake it in a jar, charge it in a whipper, or froth flavoured milk into a foam. Each gives a different texture and holds for a different length of time, so pick the one that suits the drink in front of you rather than whichever piece of equipment happens to be in the cupboard.

• Makes about 320 ml of cream, whisked or charged, which charged is eight to ten toppings and shaken about three; a foam is made one drink at a time
• Takes under a minute whisked, shaken or frothed; charged, 15 to 20 seconds of shaking and several hours' rest in the fridge
• You need a whisk, a jar with a lid, a cream whipper or a milk frother, depending on the finish

What you need

• For a cream: 300 ml of cold cream at 35 per cent fat or better, with 20 to 24 ml of syrup made from Jerk Soda Flavour Drops stirred through it
• To whisk it: a bowl and a whisk, or a hand mixer
• To shake it: a jar or a shaker with a lid that seals, and ice
• To charge it: a 500 ml stainless cream whipper with its own gasket, head and nozzle, and 8 g food-grade nitrous oxide chargers in the size and thread it is built for
• For a foam: cold milk, trim or light by default, a bottle of Jerk Soda Flavour Drops, and a frother, a coffee plunger or a jar with a lid

How to make it

Whisked cream

1. Whisk the cold flavoured cream by hand or with a mixer until it just holds its shape on the whisk.
2. Stop there. Taken further it turns grainy and then separates, and there is no bringing it back once it has.
3. Spoon it straight onto the drink. It does not keep, so whisk it close to when you will use it.

Shaken cream

1. Seal the cold flavoured cream in a jar or shaker with a handful of ice.
2. Shake it hard until it thickens around the ice rather than sloshing loosely against the sides.
3. Strain it out and pour it straight away, rather than leaving it to sit in the jar.

Charged cream

1. Stir the flavoured cream fully before it goes anywhere near the whipper. Nothing mixes for you once the head is sealed.
2. Pour it into the whipper up to its fill line: about 325 to 330 ml on a half-litre canister, and no further.
3. Seal the head the way your own model's manual describes.
4. Screw in one 8 g charger. Stop there.
5. Shake it firmly for 15 to 20 seconds, so the gas works all the way through the cream rather than sitting at the top.
6. Refrigerate the charged canister, and give it another short shake before every dispense, since the mix settles between them.
7. To serve, hold the canister upright with the nozzle close to the surface it is going onto, and let the lever run in one motion rather than several short bursts, which keeps the texture even from the first pour to the last.

Cold foam

1. Flavour the cold milk to the direction on the bottle, stir it through, then taste. Air thins out a mouthful, so a foam reads a little lighter than the milk it was made from: add another drop only if it needs one.
2. Froth it, held just under the surface with a frother or a handheld wand, or worked with a briskly pumped coffee plunger or a hard-shaken jar, until the surface is glossy with small, tight bubbles. It should still pour in a ribbon rather than stand up in a peak.
3. Pour it straight away, over the back of a spoon, so it lands on the drink as its own layer.

Warm foam

1. Flavour the cold milk first, to the direction on the bottle, stir it through and taste, whether it is going into a pan or under a steam wand.
2. In a small saucepan, heat it until it is hot to the touch and stop there: milk that boils scorches and loses the protein that was going to hold the foam. Take it off the heat and froth it with a handheld frother.
3. On a steam wand, steam and froth the flavoured milk together the way you normally would, and stop at hot to the touch.
4. Spoon or pour it straight onto the drink.

Why it works

Whisking and shaking are the same trick done two ways: air worked into the cream and held loosely by the fat around it. Both are fast and need nothing beyond a bowl or a jar, which is also why neither lasts past the next few minutes. A whipper works on a different principle. Under pressure the nitrous oxide dissolves into the cream's own fat rather than being beaten through it, and it stays in solution, sealed and cold, until the lever drops the pressure on its way out of the nozzle. That is where the close, fine texture comes from, and why a charged cream sits in the fridge for days while a whisked one is finished in minutes.

Every cream finish depends on there being enough fat left in the mix to hold anything at all. Cream whips at about 35 per cent fat and stops behaving somewhere below 30, and every millilitre of syrup stirred in is a millilitre that is not cream. 20 to 24 ml of simple or rich syrup, from How to make a flavoured syrup, sweetens and flavours 300 ml of cream and keeps the fat near 32.5 per cent, clear of the floor a charged cream needs to hold together under pressure rather than collapse into a thin foam at the nozzle.

In a whipper, the space left above the cream is where the gas sits once it comes back out of the fat, so filling past the line is the usual way a charge goes wrong. One 8 g charger is the right amount of gas for a half-litre canister rather than a cautious minimum. A second one does not make the cream lighter or keep it longer: it leaves the cream dense and coarse, and loads the canister past the pressure it was built to hold at once.

A foam is a different thing again: milk protein stretched into a thin film around air, with none of the fat a cream leans on. Fat works against that film, which is why trim or light milk is the usual choice, and added water thins it, which is why a foam takes a drop rather than a syrup. Temperature decides which foam you get. Cold, the film sets firm enough to sit on an iced drink for a few minutes; warm, it slackens, so a steamed foam pours rather than sits, which is what a coffee wants. The flavour goes into the milk before it is heated or frothed, so it is already through the milk when the foam is built.

Make it yours

• Rich syrup makes a sweeter cream and simple syrup a lighter one, but the measure does not move: 20 to 24 ml into 300 ml of cream whichever syrup is open, because that figure is set by the fat rather than the flavour.
• No whipper, or no chargers to be had. Where you can buy nitrous oxide chargers, and any rules on who may buy them, varies by region, including within Australia, so check your own retailer. Whisk or shake the cream instead, made to be used in the next few minutes.
• Making enough for a table rather than one glass: the whipper is the only finish that holds its servings for days.
• No frother to hand: a jar with a tight lid, shaken hard, froths a foam without any other equipment.
• Hazelnut is the one exception to trim milk in a foam: its flavour rides on fat, so full-cream milk carries it better.
• Pick a cream or a foam on top in the Basedrop Builder and it puts the finish on any drink, in the flavour you choose for it.

Notes

If your syrup carries an acid, leave it out of the batch you charge. Acid held in cream under pressure has not been tested, so make an acid-free batch of that syrup for the whipper.

A charger is sealed and single use. Piercing it is the same act that empties it, so there is no partial charger and no refilling one. Once it has done its job it goes into general waste or steel recycling, whichever your council collects.

Handling a charged whipper. These are ordinary instructions for a pressurised canister, not a list to skim past.

• Use only the charger your own whipper is built for, in its own size and thread. A cartridge for a different device, or gas from a bulk or tank source of any kind, is not a stand-in.
• Keep a charged whipper cold. Heat from a stove, a heater, direct sun or a hot car raises the pressure inside a canister that was never built to run hot.
• Shake it pointed away from your face and body, in case the head or the nozzle has not seated the way it should.
• Let any pressure left vent through the head's own release before you open it, following your model's instructions. Skipping that step is where most of the real risk in this method sits.
• Check the gasket before every fill. A perished, nicked or missing seal is what the whole canister depends on, and it is far cheaper to replace ahead of time.
• A whipper holds cream under gas, not a fizzy drink or anything carbonated or fermenting, which would add its own pressure on top of the charger's.

Flavour the milk before it is heated or frothed, for a cold foam or a warm one, in a pan or on a steam wand. Once milk is frothed you are tasting air as much as milk, and anything stirred in at that stage knocks the foam back down.

Plant milks

In the order they hold a foam. Soy, any grade, is the nearest to dairy and holds longest, though it carries a flavour of its own worth tasting against the drop first. Barista oat milk holds next best; an ordinary, non-barista oat milk has too little protein to foam at all. Barista almond milk is the weakest that still works, and is worth treating as a trial rather than a straight swap. Rice milk does not hold a foam: stir the drop into it and serve it as a flavoured milk instead.

Whisked, shaken or frothed, there is no hold time: make it as the drink is finished. Charged and refrigerated at 4 degrees C or below, a charged cream keeps up to 3 days, a house working ceiling rather than a verified food safety claim.

Allergens and warnings. Contains: milk, from the cream or the milk. A foam made with soy milk instead contains soy; with barista oat milk, gluten, unless the product is certified gluten free, so check its label; with barista almond milk, tree nuts (almond), and that swap is not for Hazelnut, which stays on dairy. The bottle lists what is in the flavouring, and it is the authority on that rather than this page.