Syrups, shrubs & infusions
Sugar, water, fruit, vinegar and spirit, weighed and steeped with care. The quiet ingredients that make a home cocktail taste like it came from a good bar.
Why it works
A cocktail has to balance sweet, sour, bitter and strong, and granulated sugar is useless for that job: it barely dissolves in cold, alcoholic liquid. Syrup is sugar already in solution, so it mixes in instantly and measures accurately by the millilitre. Once you make your own, the syrup also becomes a way to carry flavour: ginger, rosemary, pomegranate, autumn plums.
Measure by weight. A cup of granulated sugar weighs about 200 g and a cup of water about 240 g, and caster or coarse sugar packs differently again, so volume ratios drift. Simple syrup is 1:1 by weight, about 50% sugar. Rich syrup is 2:1, about 67% sugar. Rich syrup adds the same sweetness with less water, so drinks stay more concentrated, and its lower free water makes it harder for microbes to grow, so it keeps far longer. Use roughly two-thirds as much rich syrup as simple syrup in any recipe. The catch: 2:1 sits close to the point where water at room temperature can hold no more sugar, which is why rich syrup is the one that crystallises.
Shrubs and oleo saccharum use sugar differently. Sugar pulls moisture and aromatic oils out of fruit and peel without heat, which keeps flavours bright and fresh-tasting. Vinegar then adds acidity and helps preserve a shrub, giving you a sweet-sour concentrate that works in cocktails and in soda water alike.
Infusions rely on alcohol as a solvent. Ethanol dissolves aromatic oils and flavour compounds that water cannot, and a 40–50% spirit pulls them out quickly. It also extracts bitterness and tannin given time. Pith, seeds, stems and tea leaves give up their harsh compounds more slowly than their pleasant ones, so timing decides whether you get flavour or astringency. That is why you taste as you go.
What you need
- Digital kitchen scale: Weigh sugar, water, fruit and vinegar; ratios by weight stay consistent every batch.
- Small heavy saucepan: For warming syrups gently and steeping spices and herbs.
- Fine-mesh strainer and coffee filters: The strainer catches solids; a paper filter clears fine sediment for a cleaner bottle.
- Glass bottles and jars with tight lids: Glass does not hold smells, and you can sterilise it easily.
- Masking tape and a marker: Every bottle gets its name, ratio and date.
- Cream whipper with N2O chargers: For rapid infusions in a few minutes rather than days.
- Small funnel: Makes filling narrow bottles clean and quick.
Step by step
Weigh sugar and water
Set a jar or pan on the scale and zero it. For simple syrup, weigh 200 g sugar and 200 g water; for rich syrup, 400 g sugar and 200 g water. Plain white sugar gives a clean syrup that lets the drink speak; demerara or light brown sugar gives a rounder, toffee-like rich syrup that suits whisky, rum and brandy.
Tip: 200 g sugar and 200 g water makes about 330 ml of simple syrup, enough for twenty or so sours.
Dissolve hot or cold
Hot method: warm the water, add the sugar and stir over low heat just until the liquid turns clear. Do not let it boil, because water evaporates, the ratio shifts and the syrup can start to colour. Cold method: shake sugar and water in a sealed jar, or blitz briefly in a blender, then let it stand and shake again until no grains remain. Cold works easily for simple syrup and tastes slightly cleaner; rich syrup needs warmth to dissolve fully.
Tip: Wipe any sugar crystals from the sides of the pan or jar with a damp pastry brush. One stray crystal can seed crystallisation later.
Flavour the syrup
Spices and roots handle heat: simmer cinnamon sticks, sliced ginger or a split vanilla pod gently in the syrup for 5–10 minutes, then steep off the heat for 30 minutes to an hour. Herbs do not: take the pan off the heat first, then steep rosemary, thyme or sage for 15–30 minutes and taste. For fruit syrups, macerate chopped fruit with sugar overnight in the fridge, then warm briefly with the water and strain.
Tip: For a fiery ginger syrup, juice fresh ginger and stir in equal weight of sugar until dissolved. No heat, much more bite.
Make real grenadine
Grenadine means pomegranate. Warm 250 g pomegranate juice with 250 g sugar just until dissolved, then take it off the heat. Stir in 1 tablespoon of pomegranate molasses for depth and a few drops of orange flower water. Bottled grenadine is often just red-coloured syrup; this tastes of fruit, with a gentle sourness.
Tip: Use fresh-pressed or good bottled pure juice. Heat as little as possible to keep the fresh flavour.
Draw oil from citrus with oleo saccharum
Peel four lemons or oranges with a peeler, keeping as little white pith as possible. Toss the peels with about 100 g sugar, muddle firmly to bruise them, cover and leave for 2–4 hours at room temperature. The sugar turns wet and fragrant as it pulls out the oils. Add a splash of warm water or citrus juice, stir to dissolve and strain out the peels.
Tip: Shaken in a sealed zip bag with the air pressed out, the peels give up their oil faster and the sugar coats them evenly.
Build a shrub
Chop fruit and weigh it, then mix with an equal weight of sugar. Cover and refrigerate for 1–2 days, stirring once or twice, until a thick syrup has formed. Strain, pressing the fruit gently, and stir in vinegar equal to the original fruit weight. Bottle and leave in the fridge for a week; the vinegar's sharp edge softens and the flavours knit together.
Tip: Apple cider vinegar suits most fruit. Red wine vinegar flatters plums and blackberries; a spoon of good balsamic works with figs.
Start a spirit infusion
Put the flavouring in a clean jar and cover with spirit. Vodka gives the purest canvas; gin, light rum and bianco vermouth add their own character. Strong, fresh-tasting flavour comes fastest from 40–50% ABV. Seal, keep out of direct sun and shake gently once a day.
Tip: Bruise herbs, crack whole spices and slice fruit thinly. More exposed surface means faster, more even extraction.
Taste often, then strain
Taste a few drops on a spoon at the times in the table below, and more often for chillies and tea. Strain the moment it tastes right; the flavour stops developing once the solids are out. Pour through a fine-mesh strainer, then through a coffee filter if you want it clear.
Tip: If you overshoot, dilute with more of the base spirit. Bitterness never goes back into the leaves.
Speed it up when you need to
In a cream whipper, add spirit and solids, charge with one or two N2O cartridges, swirl and wait 1–5 minutes. Hold the whipper upright and vent the gas quickly into a container; the sudden pressure drop forces flavoured liquid out of the solids. Let the bubbling stop, then strain. For sous vide, seal spirit and flavourings in a zip bag using the water displacement method, cook at 55–60 °C for 1–2 hours, then chill in iced water before opening.
Tip: Use only N2O. A CO2 charger carbonates the liquid and makes it taste sharp.
Bottle, label and chill
Funnel syrups and shrubs into sterilised bottles while warm or cold, cap, and refrigerate. Label each with its name, ratio and date. Infused spirits keep in a cupboard once strained, since the alcohol protects them, though fresh fruit flavours fade over months.
Syrups and how long they keep
| Syrup | Ratio | Method | Keeps (fridge) |
|---|
| Simple syrup | 1 sugar : 1 water | Hot or cold | 3–4 weeks |
| Rich syrup | 2 sugar : 1 water | Warm until clear | Up to 3 months |
| Demerara rich syrup | 2 sugar : 1 water | Warm until clear | Up to 3 months |
| Honey syrup | 3 honey : 1 water, or 2:1 to pour more easily | Stir into warm water, no boiling | 1–2 months |
| Agave syrup | 2 agave : 1 water | Stir cold | 1–2 months |
| Ginger syrup | 1 ginger juice : 1 sugar | Cold, stir to dissolve | 2 weeks |
| Cinnamon or vanilla syrup | Simple or rich, plus spice | Simmer 5–10 min, steep, strain | 3–4 weeks |
| Rosemary or herb syrup | Simple syrup, plus herbs | Steep off the heat 15–30 min | 2 weeks |
| Fruit syrup | Fruit macerated in 1:1 syrup | Macerate, warm briefly, strain | 1–2 weeks |
| Grenadine | 1 pomegranate juice : 1 sugar | Warm just to dissolve | 3–4 weeks |
| Oleo saccharum | Peel of 4 citrus : 100 g sugar | Muddle, rest 2–4 h | 1–2 weeks once dissolved |
| Shrub | 1 fruit : 1 sugar : 1 vinegar | Cold, 1–2 days, then vinegar | 3–6 months |
Infusion times by ingredient
| Ingredient | Typical amount | Time | Watch for |
|---|
| Hot fresh chillies (habanero, bird's eye) | 1–2, halved | 10 min – 2 h | Heat builds fast; seeds add more |
| Milder chillies (jalapeño) | 2–3, sliced | 1–6 h | Green, vegetal notes if left long |
| Tea (black, green, chamomile) | 10–15 g | 10–30 min | Tannin and bitterness |
| Soft herbs (basil, mint) | 1 large handful | 2–6 h | Grassy, cooked flavour |
| Woody herbs (rosemary, thyme) | 3–4 sprigs | 6–24 h | Resinous, medicinal taste |
| Citrus peel, pith removed | Peel of 2–3 fruit | 1–2 days | Bitterness from any pith |
| Fresh ginger | 50 g, sliced | 1–3 days | Becomes harsh, not hotter |
| Coffee beans, coarsely cracked | 50 g | 12–24 h | Bitterness and over-extraction |
| Whole spices (cinnamon, star anise, cloves) | 1–2 sticks or a few pieces | 1–3 days | Cloves and star anise dominate quickly |
| Vanilla pod | 1, split | 2–5 days | Rarely harsh; can turn woody |
| Fresh fruit (berries, apple, pear, quince) | 300–400 g | 3–7 days | Fades and goes jammy |
| Dried fruit (figs, apricots, raisins) | 150–200 g | 3–7 days | Sweet and heavy |
Troubleshooting
My syrup has crystallised in the bottle
Rich syrup sits close to saturation, so a stray undissolved grain, a cold fridge or a little evaporation sets it off. Warm the bottle in a pan of hot water with a splash of water added, stir until clear, and pour into a clean bottle. Next time, dissolve fully, wipe crystals from the rim, and add a teaspoon of glucose syrup or honey per 500 ml to help prevent it.
There is mould on top, or it smells sour and fizzes
Yeasts and moulds have taken hold, usually in a simple or fruit syrup that was kept too long or bottled in an unclean container. Throw the whole bottle away; skimming does not remove what you cannot see. Use sterilised bottles, make smaller batches and switch to rich syrup if you use it slowly.
The infusion turned bitter
It steeped too long, or the solids included pith, seeds, stems or tea leaves that release tannin. Strain at once and dilute with more of the base spirit until it tastes balanced. Next time remove pith carefully, taste earlier, and pull delicate ingredients sooner.
The infusion tastes weak
Too little flavouring, too little time, or pieces too large to give up their flavour. Add more fresh material, crush or slice it more finely, and give it longer. A stronger base spirit extracts more quickly, and a short burst in a cream whipper can finish the job.
My syrup or infusion is cloudy
In fruit syrups and shrubs, pectin and fine pulp cause haze; in infusions, tiny particles or citrus oils that come out of solution. Let the bottle settle in the fridge overnight, pour off the clear liquid and filter it through a coffee filter. If a syrup that was clear turns cloudy on its own, that is spoilage: discard it.
My honey syrup is too thick to pour
At 3:1 honey syrup stiffens in the fridge. Stand the bottle in warm water for a few minutes before service, or make it 2:1 instead. Never boil honey; it loses its delicate aromas.
Hot sugar, clean bottles, cold storage
Hot syrup clings to skin and burns badly, and anything sweet and wet is food for microbes. Work carefully and keep everything clean and cold.
- Keep children away from the stove while syrup is hot, and let it cool before tasting or pouring into thin glass.
- Sterilise bottles: wash in hot soapy water, rinse, and dry in the oven at 140 °C for 10–15 minutes, or run them through a hot dishwasher cycle.
- Keep all syrups, shrubs and fruit concentrates in the fridge, and throw out anything that smells off.
- Infuse in spirits only. Fresh herbs, garlic or chilli kept in oil at room temperature can harbour botulism; high-proof alcohol does not carry that risk.
- Never infuse near an open flame; alcohol vapour catches fire easily.
- Infused spirits taste softer than they are. Measure pours, and offer a shrub with soda water to anyone driving or pregnant.
