General tips
Steep aromatics in the cream first. Vanilla beans, citrus zest, cinnamon sticks, or saffron threads need 15–20 min off-heat in warm cream to release their flavor compounds. Sous vide can't infuse aromatics in 1–2 h the way a slow infusion does.
Strain twice - once after combining the egg yolks with the cream, once before pouring into jars. The first strain catches any cooked egg from the temper; the second catches any solid bits from the aromatics. Two passes for true silk texture.
Use 4-ounce Mason jars and don't fill past the shoulder. Custard needs space to set evenly without the center curdling, and overfilled jars cook unevenly. The shoulder line is roughly 80% full - that's your fill point.
Sous vide at 176°F for 1 h for flan-firm texture. Push to 180°F for 90 min if you want a denser, more solid set for unmolding. The temperature controls density more than the time does - once the eggs coagulate, they don't change much.
Anti-tip: don't try to unmold while warm. Even fully-set custards need a full overnight chill to firm up enough to invert without collapsing. Run a thin knife around the inside of the jar, then dip the bottom in hot water for 10 sec before flipping.
Soft Custard tips
Strain the custard base through a fine sieve to remove any cooked egg bits.
Skim any foam off the top before portioning so the surface stays glassy.
Let jars cool to room temp before refrigerating to prevent condensation drips.
Firm tips
Run a thin spatula around the edge before unmolding for clean sides.
Use silicone molds if you want perfectly shaped egg bites or mini cheesecakes.
Torch or sear cut sides in butter to add a caramelized crust.