A yoghurt sauce
In the first three, something turned out well or badly. Here something BREAKS, and the break does not reverse. 85 °C is not a target but a ceiling: stay under it and you have a sauce, pass it and it splits into something else.
Change them and see
Properly tempered
The classic proportion. The swollen starch keeps the casein particles from colliding and the lecithin in the yolk holds the fat and water interface. The ceiling is still 85, but approaching it is no longer a disaster.
In order, minute by minute
Not a list of steps but a timeline: each one carries the minute it happens at and the temperature it happens at. Changing the order changes the result, and this shape is why the engine can say so.
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0 minutes
Whisk the yoghurt, flour and yolk together in a separate bowl until smooth.
The liaison has to arrive ready. Flour that has not dispersed in the yoghurt will lump the moment it meets hot liquid, and never builds the protective net.
What to look for Smooth and pourable, with no lumps.
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3 minutes 60 °CCritical point
Add the hot liquid to the liaison a ladle at a time, not the other way round. At least five ladles, whisking between each.
This is the entire technique: bring the pot to the yoghurt rather than the yoghurt to the pot. Cold yoghurt meeting boiling liquid sets the casein at the contact surface instantly, and that curd never disperses again. Adding it a ladle at a time raises the temperature slowly and never delivers the shock.
What to look for The liaison should feel warm rather than hot, around 55–60 °C: the bowl is warm to hold, not uncomfortable.
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8 minutes 80 °C
Return the warmed liaison to the pot and thicken it over a low heat, stirring. DO NOT BOIL.
At 62 °C the starch begins to gelatinise and that is where the body comes from. At 85 the casein micelles lose their charge, clump and release the water they were holding. The twenty-three degrees between them is the whole working range of the sauce.
What to look for It coats the back of a spoon. If you see a bubble you are already late.
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12 minutes 70 °C
Off the heat. Garlic, mint or sizzled butter go in now.
The aroma compounds in garlic and fresh herbs are volatile: in a boiling pot they are the first to leave and only the sharpness stays. Garlic added off the heat stays in the sauce.
What to look for The smell lifts, and the sauce stays glossy and whole.
The numbers that decide it
Properly tempered
Read off the amount of liaison. It buys resistance, not immunity: past 85 °C it still splits, only later.
15
More starch means more body, and past a point the acidity of the yoghurt disappears under the flour.
18
The yolk holds the emulsion with its lecithin and rounds the sauce out. More of it also buys a little more tolerance at the ceiling.
What is happening in the pot
- < 62 °C Starch still asleep The granules are just floating there doing nothing. No body arrives before 62 °C. Held in the system
What happened, why, and what to do
Some of these can be saved and some cannot. Writing up the second kind as though it were the first costs somebody another twenty minutes.
01 The sauce is grainy with white specks ⌄
Why
It reached 85 °C. The casein clumped and let go of its water.
Can be saved
Blend it: the grain breaks up and the sauce is perfectly edible, if never quite as silky. A spoonful of starch slurry helps it come back together.
02 It split the moment the liaison went in ⌄
Why
The temperature gap was too wide: cold yoghurt met boiling liquid.
Cannot be saved
This pot is gone, and the lesson is plain: the hot liquid goes into the yoghurt, never the yoghurt into the hot liquid.
03 No body; it stayed like water ⌄
Why
After the liaison went in, the pot never reached 62 °C and the starch never woke.
Can be saved
Bring it to 75–80 on a low heat, stirring, and hold it there. Do not approach 85.
04 It tastes of flour ⌄
Why
Too much starch, or it never cooked out. Raw starch leaves a powdery feel.
Can be saved
Two or three more minutes on a low heat — but the 85 ceiling still applies, so buying that time costs you risk.
Watch out Raw or lightly cooked egg carries a salmonella risk. Use pasteurised egg for mayonnaise, tiramisu and the like, and do not serve raw egg to anyone pregnant, to infants, to the elderly or to anyone immunosuppressed.
The safety check does not know the following. That is not the same as nothing being wrong — it means nobody looked, and anything meant to keep at room temperature has to be measured rather than assumed.
- Water activity
This is a model estimate rather than a measurement. How far each threshold behind it has been checked is below; fourteen of the fifteen still have no source on file, and saying so is better than not.
engine 1.0.0 · ruleset 2026.09.1 · confidence medium
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