What your result means
Time to target is how long the pan needs to reach the stage you picked, almost all of it spent boiling water away. Sugar at target is the concentration the syrup must reach for that temperature — the two are the same measurement, which is the insight the candy thermometer is built on.
Water boiled off is what leaves the pan as steam on the way. Pan settles at is the temperature where your hob's heat is exactly matched by heat lost and by the caramelisation reaction itself soaking energy up — turn the power up and that ceiling rises, which is the difference between amber caramel and a black pan.
Why this one is different
Time to your target temperature comes with the sugar concentration reached at that moment, because the two together are what decide the texture rather than the temperature alone. Water boiled off is tracked, and the temperature the pan settles at is stated, which is why a syrup stalls short of the reading you were waiting for.
How it works
While there is water in the pan, the temperature cannot run away: it is pinned to the boiling point of the syrup, and that boiling point depends only on how concentrated the syrup is. 80% sugar boils at 110 °C, 85% at 114 °C, 98% at 149 °C. So a thermometer in a sugar pan is really a concentration meter, and every candy stage is a sugar percentage wearing a temperature as a label.
Once the last of the water has gone, the pinning stops and the sugar itself starts to come apart. Sucrose molecules break up and recombine into hundreds of new compounds — that is caramelisation, and it is what produces both the colour and the bitter-toasty flavour. The reaction speed follows temperature exponentially, roughly doubling every 8 °C, so the last twenty degrees matter more than the first hundred.
Caramelisation also absorbs heat as it goes, which is why a pan of caramel tends to hold at a temperature rather than rocketing to burnt: the reaction is eating the energy the hob is supplying. Where it holds depends on your power setting, and that is the figure the panel calls the settling point. Note that this is sugar alone — brown a sauce with milk or eggs in it and you are into the protein reactions as well.
How to use this simulator
- Set your sugar and water as the recipe gives them.
- Set the hob power. This is the control that decides whether you get caramel or charcoal.
- Pick a target stage and read the time — then press play and watch the graph cross it.
- Press jump to target to skip the boiling and land on the moment that matters.
- Now set water to zero. Dry caramel reaches colour far sooner, and is far easier to ruin.
Formula
concentration: c = mₛ ÷ ( mₛ + mᵤ )
while wet: T = Tᵇ( c ) and dmᵤ/dt = −( Pₙ − Pᵣ ) ÷ Lᵥ
once dry: dT/dt = ( Pₙ − Pᵣ ) ÷ ( mₛ · cₚ )
browning rate: k = A · e^( −Eₐ ÷ R T )
reaction sink: Pᵣ = ΔH · mₛ · k
- Tᵇ(c) — boiling point of a sucrose solution at that concentration, from the measured ladder
- Lᵥ — latent heat of vaporisation of water, 2257 kJ/kg
- cₚ — specific heat of molten sugar, 1.24 kJ/kg·K
- Eₐ — activation energy for caramelisation, 140 kJ/mol; R — the gas constant
- ΔH — heat absorbed by the reaction, which is what creates the settling point
Example calculation
500 g of sugar with 150 ml of water on a 1500 W ring, aiming for hard crack:
soft ball, 114 °C and 85% sugar, at 4:09
hard crack, 149 °C and 98.4% sugar, at 7:29 — 142 g of water gone
amber colour by 8:41, and burnt by 10:04
the pan settles at 164.8 °C
Those are the simulator's starting values and the panel shows the same figures. Note the shape of it: three-quarters of the time goes on boiling water, and the entire journey from perfect amber to ruined takes about 80 seconds. Turn the ring down to 800 W and the pan settles at 155 °C instead — slower, and much harder to burn.
The candy ladder is a concentration ladder
Which is why the same recipe reaches the same stage whether you started with a splash of water or a cupful. Halving or doubling a batch changes the timings but not these numbers — the recipe scaler handles the quantities.
Frequently asked questions
Why does caramel go from amber to burnt in seconds?
Because the browning reaction roughly doubles in speed for every 8 degrees Celsius. Getting from 150 to 170 is therefore not a small step, it is about a fivefold increase in rate, and by then there is no water left to soak up the heat. The temperature also climbs fastest exactly when the colour is changing fastest, which is why caramel needs watching rather than timing.
Does adding water change the final caramel?
No. Water only sets how long the first half takes, because all of it has to boil off before the sugar can pass 150 degrees. What water buys you is control: it dissolves the sugar evenly so no dry patch scorches while the rest is still melting. The caramel you end up with is the same either way.
Why do recipes tell you not to stir sugar syrup?
Stirring flicks syrup up the side of the pan where it dries into crystals, and a single crystal falling back in can set the whole batch grainy. This simulator models concentration and temperature but not crystallisation, so it will happily show a smooth syrup where a real unstirred pan might seize. Brushing the sides down with water, or adding a spoon of glucose or lemon juice, is what prevents it in practice.
Related calculators
Assumptions & limitations
- 75% of the hob's power reaches the pan, with losses rising as it gets hotter. A thin pan on a big ring does worse; a heavy pan with a lid does better.
- The last grams of water leave asymptotically. Concentration approaches 100% without ever arriving, so times quoted for the very top of the ladder are optimistic.
- Browning is a single calibrated reaction. The activation energy is taken from published caramelisation kinetics, but the colour index and the heat it absorbs are calibrated to give realistic timings rather than measured in a lab.
- Crystallisation is not modelled. Neither is inversion of sucrose by acid, which real recipes exploit to keep syrup smooth.
- Pure sucrose, at sea level. Glucose, honey and brown sugar behave differently, and every stage temperature falls by roughly 1 °C per 300 m of altitude.
- No Maillard browning. The Maillard reaction is the other way food browns: sugars reacting with protein, rather than sugar breaking down on its own. It is what browns a steak, a crust or a roast onion, it starts around 140 °C, and it produces savoury flavours rather than the bitter-toasty ones here. This simulator models pure sugar, so it is caramelisation only — add dairy, eggs or flour and both reactions run together.
Further reading
Our guide to kitchen chemistry explains why caramelisation and the Maillard reaction are not the same browning, and what each one needs. The rest of The Kitchen & Gut Lab covers what your other ingredients are doing while the sugar cooks.
Sources & references
The boiling ladder, the latent heat and the caramelisation kinetics used here come from the following, all specific to sugar cooking.
- NIST Chemistry WebBook — water, the 2257 kJ/kg latent heat of vaporisation that dominates the timings
- Starzak & Mathlouthi (2006), Food Chemistry — water activity in sucrose solutions, the thermodynamics behind the boiling-point ladder
- Quintas et al. (2007), Journal of Food Engineering — colour development kinetics in sucrose thermal degradation, the source of the activation energy
- National Center for Home Food Preservation — candy stage temperatures as used in the target list