Cooking Substitutions and Conversions: UK Ingredient Swaps, Weights and Oven Temperatures

Overview

Good substitutions are not always one-for-one. An ingredient may add moisture, fat, acidity, sweetness, structure, seasoning or thickening, so the best replacement depends on the job it performs in the recipe. Replacing self-raising flour with plain flour, for example, means replacing the raising agent as well; swapping yoghurt for milk changes both thickness and acidity.

Before making a change, identify the recipe type. Ingredient swaps are usually more forgiving in soups, stews, sauces and savoury tray bakes than in cakes, meringues, pastry and bread. In baking, small changes to liquid, fat or raising agents can affect the final texture. If a recipe is unfamiliar, make the smallest sensible adjustment first and write down what you changed.

Quick UK conversion chart

Cups are a volume measure, while grams are a weight measure. There is no single cups-to-grams conversion for every ingredient. A cup of flour, sugar, butter and chopped nuts will all weigh different amounts. For baking, use the recipe's stated ingredient-specific conversion where possible rather than applying one general figure.

Oven temperature conversion

These are practical rounded equivalents. Oven performance varies, so use the recipe's visual and texture cues as well as the displayed temperature. A fan oven commonly cooks more quickly or evenly than a conventional oven; if a recipe does not specify the oven type, check the food early rather than assuming the cooking time will be identical.

Checklist by scenario

You are missing a savoury ingredient

• Onion: use leek, shallot or spring onion. The flavour will be milder or fresher, so cook until soft and adjust seasoning.
• Garlic: use garlic granules, garlic paste or a small amount of finely chopped wild garlic when suitable. Add dried garlic carefully because its flavour is concentrated.
• Fresh herbs: use dried herbs, but start with less and add more after tasting. Dried herbs need time in the dish to soften and release flavour.
• Stock: use water with appropriate seasoning, or a suitable stock cube or paste. Taste before adding extra salt.
• Cream: use crème fraîche, plain yoghurt, evaporated milk or full-fat milk depending on the recipe. Add yoghurt or crème fraîche gently at the end to reduce the risk of splitting.
• Lemon juice: use lime juice or a small amount of mild vinegar when acidity is the important function. Add gradually because vinegar can taste sharper.

You are adapting a baking recipe

• Self-raising flour: replace it with plain flour plus baking powder, using the raising-agent guidance in the recipe where available. Do not assume plain flour alone will give the same lift.
• Buttermilk: use plain yoghurt loosened with milk, or milk soured with a little lemon juice. This works best where the recipe also contains bicarbonate of soda or another raising agent.
• Egg: in some cakes, a prepared egg replacer, mashed banana or apple purée can provide binding and moisture. The result may be denser or have a noticeable flavour, so use a recipe designed for that substitution when possible.
• Butter: baking margarine can work in many cakes and biscuits, but spreads and oils do not behave identically. Check whether the recipe relies on butter being creamed with sugar or chilled into pastry.
• Ground almonds: use another ground nut only if allergies are not a concern. Flour or breadcrumbs may absorb moisture differently and will not provide the same richness.

You need to scale a recipe

Use this formula: new quantity = original quantity × new number of portions ÷ original number of portions. For example, to turn four portions into six, multiply every ingredient by 6 ÷ 4, or 1.5. Scale main ingredients, liquids and seasonings, then review the result rather than blindly increasing salt, chilli or strong spices.

Scaling cooking time is less exact. A larger casserole may need more time to heat through, while a deeper cake may need a lower temperature and longer bake. A doubled tray bake may also need a larger tin rather than simply becoming deeper. Keep the food's safe doneness and texture as the final test.

What to double-check

1. Allergens: a substitution is not automatically allergen-free. Check every packet, including stock, chocolate, margarine, spice blends and ready-made sauces. Avoid cross-contamination when cooking for someone with an allergy.
2. Dietary suitability: vegetarian, vegan, halal, kosher and gluten-free requirements may affect several ingredients at once. For example, replacing meat does not necessarily replace the stock or sauce used with it.
3. Moisture: yoghurt, fruit purée and grated vegetables add water. If a mixture looks loose, hold back some other liquid; if it looks dry, add liquid a teaspoon or tablespoon at a time.
4. Acidity: bicarbonate of soda needs acidity to work effectively. Replacing an acidic ingredient with a neutral one may leave a bake heavy or affect its colour.
5. Cooking time: smaller pieces cook faster, while a crowded tray, larger joint or deeper dish cooks more slowly. Use colour, tenderness and internal temperature where appropriate, not time alone.
6. Equipment: air fryers, fan ovens and slow cookers vary. For appliance adaptations, use the relevant slow cooker conversion guide or air fryer cooking times guide as a starting point.

Common mistakes

• Confusing US cups with UK cups. Check which country the recipe comes from before measuring.
• Converting flour, sugar or butter from cups to grams using the same number. Ingredient density makes that inaccurate.
• Replacing a liquid with a solid, or a solid fat with oil, without considering how the mixture will change.
• Adding all the substitute at once. Hold back part of a liquid or strong seasoning and adjust after mixing.
• Opening the oven repeatedly to check a delicate cake, which can affect baking. Use the recipe's suggested test, such as a skewer or gentle spring.
• Scaling salt and spices mechanically. Main ingredients can be multiplied precisely, but seasoning is usually best adjusted gradually.
• Assuming a swap will preserve the original result. Aim for the recipe's function first: tender, crisp, thick, light, rich or well-seasoned.

For more practical planning, pair these checks with UK meal prep and batch cooking guidance. If you are baking, the beginner's British baking guide is a useful place to choose recipes with clear, tested methods.

When to revisit

Keep this guide handy when planning a weekly shop, adapting seasonal recipes or cooking from an overseas cookbook. Revisit the conversion tables whenever a recipe uses an unfamiliar cup system, a different oven type or a new appliance. It is also worth checking your own notes after testing a substitution: record the brand, quantity, texture and cooking time so the next attempt is more predictable.

Before you start, run through this short action list:

1. Identify what the missing ingredient does in the recipe.
2. Choose a replacement with a similar function, not merely a similar name.
3. Check allergens, dietary requirements and packet instructions.
4. Convert measurements using the correct ingredient and cup system.
5. Adjust liquid, seasoning and cooking time gradually.
6. Test the finished food for texture, flavour and doneness before serving.

When the result matters—particularly for celebration cakes, bread, pastry or food prepared for allergy-sensitive guests—use a recipe written for the required substitution where possible. For everyday soups, sauces, stews and family meals, this checklist gives you a sensible way to adapt what you already have.