Last updated: · Maintained by Lee Harsh (Full-Stack Developer)
Blended vegetable soups (potages) use a 3 : 4 vegetable-to-liquid weight ratio—750g of prepared root or green vegetables sweated in 35g butter with 150g aromatics, simmered in 1,000mL (1 litre) of stock, and finished with 75mL cream—yielding approximately 1,700mL (1.70 litres), enough for six 285mL starter bowls or four 425mL main-course bowls.
Worked Example: To scale a 6-starter-bowl carrot and coriander soup (750g peeled carrots, 150g diced onion, 35g butter, 1,000mL vegetable stock, 75mL cream = ~1.70L) for 15 guests (2.5× multiplier), sweat 1,875g sliced carrots and 375g diced onion in 88g butter under a lid for 12 minutes, simmer in 2,500mL stock for 22 minutes, and blend smooth with 188mL cream and 40g fresh coriander to yield ~4.25 litres.
| Soup / Potage Style | Veg-to-Stock Ratio | Prepared Solids per 1L Stock | Thickening Mechanism | Finished Volume per 1L Stock |
|---|---|---|---|---|
| Blended Root Potage (Carrot, Squash, Parsnip) | 1 : 1.33 | 750g diced root veg + 150g onion | Pectin & softened cellular fiber puree | ~1.70 Litres (6 starter bowls @ 285mL) |
| Leafy Green Velouté (Watercress, Pea & Mint) | 1 : 1.43 | 500g greens + 200g starchy potato | Potato amylopectin + 4m blanch for green color | ~1.60 Litres (5–6 starter bowls) |
| Oven-Roasted Tomato & Basil Soup | 1 : 0.83 | 1,200g halved ripe plum tomatoes | Roasting at 200°C evaporates ~25% water | ~1.65 Litres (concentrated tomato body) |
| Hearty Broth (Beef Barley, Minestrone, Borscht) | 1 : 1.50 | 550g veg/meat + 120g pearl barley | Gelatin stock body + barley starch release | ~1.75 Litres (4 generous 435mL bowls) |
| Creamy Chowder / Jerusalem Artichoke | 1 : 1.25 | 800g diced tubers or smoked fish | 30g butter + 30g flour blond roux + cream | ~1.75 Litres (velvety spoon coating) |
Blended vegetable soups (potages and veloutés) achieve a spoon-coating texture without heavy flour thickeners when prepared vegetables and cooking stock follow a 3 : 4 weight-to-volume ratio: 750g of peeled, diced root or green vegetables sweated with 150g onion/leek aromatics in 35g butter, simmered in 1,000mL (1 litre) of stock, and finished with 75mL double cream or coconut milk.
Because diced vegetables retain roughly 85% of their mass as pureed volume after sweating and simmering, that 750g vegetable + 1,000mL stock + 75mL cream base yields approximately 1,700mL (1.70 litres) of finished soup—serving six 285mL starter bowls or four 425mL main-course bowls.
For classic carrot and coriander soup, butternut squash potage, or parsnip and apple soup, sweat the sliced vegetables and onions in butter with a pinch of salt under a tight cartouche (parchment lid) over low heat for 12 minutes before adding stock. Sweating at 95°C–105°C softens pectin in the plant cell walls and concentrates natural sugars without browning and muddying the soup's bright color.
By contrast, roasted tomato and basil soup relies on high-heat Maillard caramelization: toss 1,200g halved plum tomatoes, garlic cloves, and 30mL olive oil on a sheet pan and roast at 200°C Conventional (180°C Fan / 400°F) for 35 minutes to evaporate ~25% of the free water before simmering with 1,000mL stock.
Green leafy soups—such as watercress soup, petit pois and mint velouté, or courgette and basil potage—turn dull olive-brown if simmered longer than 4 to 5 minutes because heat and organic plant acids strip the central magnesium atom from chlorophyll molecules.
To lock in vivid emerald color, simmer 200g diced starchy potato and 150g leek in 1,000mL stock for 15 minutes until tender first, then stir in 500g watercress or peas to boil uncovered for just 3 to 4 minutes, blend immediately at high shear, and chill the pot base in an ice bath if making ahead.
In unblended broths like beef and pearl barley soup, Tuscan bean minestrone, or beetroot borscht, increase the stock ratio to 1 : 1.50 (1,000mL stock to 550g meat/vegetables plus 120g dry pearl barley or pasta), remembering that dry barley absorbs 3× its weight in liquid during a 45-minute simmer.
For creamy smoked haddock chowder or Jerusalem artichoke soup, whisk 30g plain flour into 30g foaming butter for 2 minutes to form a blond roux before adding 1,000mL stock and milk so the dairy emulsion never splits when reheated.
When batch-cooking 3 to 5 litres of carrot and coriander potage, roasted tomato soup, or beef barley broth, cool the stockpot in a sink filled with ice water—stirring every 5 minutes—so the soup passes through the 60°C-to-20°C bacterial danger zone within 60 minutes before ladling into 500mL freezer tubs. Freeze blended vegetable bases BEFORE adding finishing double cream, whisking fresh cream in when reheating to a gentle 85°C simmer.
Our 3:4 vegetable-to-stock hydration equations and bowl-yield tables are independent culinary calculations grounded in USDA volume-to-mass data, unaffiliated with any television chef.
Use a 3 : 4 vegetable-to-liquid ratio: 750g of prepared diced vegetables (plus 150g onion sweated in 35g butter) simmered in 1,000mL (1 litre) of stock and finished with 75mL cream yields ~1.70 litres of potage.
Because 750g of pureed vegetables retains ~85% of its weight as volume (~635mL), combining it with 1,000mL stock and 75mL cream produces ~1,700mL (1.70L) of finished soup—enough for six 285mL starter bowls or four 425mL main-course bowls.
Sweating sliced carrots, squash, and onions gently in butter under a parchment cartouche or lid at 95°C–105°C for 12 minutes softens plant cell pectin and concentrates sweetness without browning the vegetables.
Simmer the potato and leek base in stock for 15 minutes until tender first, then boil the watercress or peas uncovered for just 3 to 4 minutes and blend immediately so heat and organic acids do not strip magnesium from the green chlorophyll.
Oven-roasting 1,200g halved plum tomatoes at 200°C (180°C Fan) evaporates ~25% of their water and pairs with 1,000mL stock (1 : 0.83 ratio), whereas beef and pearl barley broth uses 1,000mL stock to 550g meat/vegetables and 120g dry barley (1 : 1.50 ratio).
No—all soup ratios and litre yield equations in this tool are independent culinary math references grounded in USDA FoodData Central weights, unaffiliated with any named chef.
Explore our 7 core culinary and nutrition calculators, 18 archetype scaling hubs, and primary scientific reference databases:
Static food blogs lock every recipe to a single yield, a single cake tin size, and a single oven type—leaving you to guess when converting an 8-inch sponge to a 2lb loaf tin, boiling blackberry jam to 105°C, or smoking Famous Dave's ribs at 225°F.
Our deterministic calculator applies verified UK/US gram densities, pan surface-area ratios, AGA/Smoker/Slow Cooker offsets, and Mary Berry All-in-One method simplifications automatically in one place.
Scale your ingredients, convert cake tins and appliances, and export your recipe checklist with confidence.
Start Scaling & Converting