Praline is caramelised nuts ground to a flowing paste. Smoothness is achieved by mechanics rather than by formula: the particles have to become small enough that the tongue stops registering them, and the oil released from the nuts during grinding has to stay in emulsion rather than rise to the top.
Hence the two principal faults. Grittiness means the grinding was not taken to the end. Separation means the oil has come out and floated.
Roasting the nuts
The first stage, and it governs both the flavour and the behaviour during grinding. Roast at 150–160 °C for 12 to 18 minutes depending on the nut, until the aroma is steady and the cut face is golden.
Under-roasted nuts give a pale flavour and, more importantly, release their oil less readily — the paste stays thick and gritty for longer. Over-roasted nuts turn bitter, and bitterness in a paste is masked by nothing.
Hazelnuts are skinned after roasting: the skins will not grind down and stay as noticeable specks that are easily mistaken for under-grinding.
The nuts must cool completely before meeting the caramel. Warm nuts soften the caramel and it will not set properly.
Caramel temperature
A dry caramel is cooked to 170–175 °C. The window is narrow, and both edges show up in the finished paste.
Under-cooked caramel, below 160 °C, stays soft and sticky. During grinding it does not shatter but smears, clogging the blades — the paste comes out stringy and never gains fluidity.
Over-cooked caramel, above 185 °C, turns bitter and brittle to the point of crumbling, and that bitterness combined with the nut gives an unpleasant sharpness.
The nut and caramel mixture is poured onto a silicone mat in a thin layer and cooled completely to room temperature. A warm mass goes straight to paste under the blades, skipping the granular stage — and that is one of the ways it overheats.
Grinding in three stages
The key to smoothness is understanding that grinding passes through three distinct states, and not panicking at the second.
- Rubble. The first minutes, the mass breaks into large pieces. Nothing is happening.
- Sand, then a ball. The mass turns to powder, then suddenly gathers into a dense ball around the blade. This is a normal and necessary stage — and it is where most people stop, deciding something has gone wrong.
- Paste. The nuts release their oil, the ball loosens and turns into a flowing mass. This happens all at once.
At the ball stage the machine has to be stopped several times and the mass scraped down from the sides before continuing. Total time is 10 to 20 minutes in a powerful cutter, up to forty in a domestic blender, with compulsory pauses.
Grittiness on the tongue means the process was stopped at the second stage, or at a third that was never finished. As a guide, a paste counts as smooth once the particles are below 25–30 microns — in practice, once a drop rubbed between the fingers gives no sensation of sand.
Overheating the bowl
The main cause of separation. Friction heats the mass, and under continuous running the temperature easily reaches 50–60 °C.
What happens: the oil released from the nuts stops being held in the mass at that temperature and separates completely. Once cooled you have a layer of oil on top and a dense sediment below.
The working limit is 45 °C. In practice that means pauses: three or four minutes of running, then five minutes of cooling. You can check by hand against the side of the bowl — if it is noticeably hot rather than warm, stop.
What to do with a separated paste
Almost always recoverable. Let the paste cool to room temperature, then stir it vigorously with a spatula or blend briefly at low speed. The emulsion comes back together.
If it separates repeatedly, add a stabiliser — a small amount of milk or dark chocolate, 5 to 10 % of the mass. The cocoa butter gives the system structure and holds the nut oil.
Separation during storage, incidentally, is not a fault in itself: pure praline with no stabiliser always separates over time, and you simply stir it before use. Any natural nut butter behaves the same way.
Storage
Sealed at 16–18 °C, praline keeps for two to three months. There is one enemy: oxidation of the nut oil. A rancid note comes from contact with air and light rather than from time as such.
The fridge is not worth using: the paste thickens, and on returning to room temperature it separates more readily.
Finished pralines and the pieces built on them are covered in the masterclasses Hazelnut Praline and Black Sesame Praline.