Ganache, Mirror Glazes, and Poured Finishes

Ganache, Mirror Glazes, and Poured Finishes

A perfectly poured finish transforms a simple mousse round into a showpiece. This lesson covers the science behind ganache emulsions, the mechanics of mirror glazes, and the hands-on technique of glazing an entremet-style cake.

The Science of Ganache

Ganache is an emulsion: fat droplets from chocolate and butterfat are suspended in the water phase of cream. A stable emulsion requires proper technique — gentle heat, thorough agitation, and, ideally, an immersion blender to reduce droplet size and create a uniformly smooth texture.

The cream-to-chocolate ratio is the single most important variable controlling final consistency:

• Firm ganache / truffle center (1:1 chocolate:cream by weight): Equal parts produce a ganache that sets firm enough to roll into truffles at room temperature. At this ratio, dark chocolate ganache is dense and scoopable when cool.
• Soft ganache / glaze (1:2 chocolate:cream, or 2 parts cream to 1 part chocolate by weight): More cream keeps the ganache fluid and pourable at a wider range of temperatures, making it ideal for coating or filling.
• Pouring glaze (approximately 1:1 chocolate:cream with added glucose): Adding glucose or corn syrup increases viscosity and shine, slows crystallization, and gives the glazed surface a longer window of workability.

White chocolate behaves differently from dark because it contains no cocoa solids — only cocoa butter, sugar, and milk solids. White chocolate is more sensitive to heat (scorch easily above about 110 °F / 43 °C) and requires a higher chocolate-to-cream ratio to achieve the same body as dark chocolate ganache.

Temperature Control

Temperature governs everything:

• Too hot (above ~95 °F / 35 °C): Ganache is very thin and will run off the cake, pooling at the base and leaving thin or bare spots on top.
• Working range (~86–90 °F / 30–32 °C for dark ganache glaze): The ganache flows smoothly, self-levels, and coats in one pass. Use a digital thermometer to confirm temperature before every pour.
• Too cool (below ~80 °F / 27 °C): Ganache becomes sluggish, pulls rather than flows, and sets with drag marks or an uneven surface.

White chocolate mirror glaze typically pours well in a slightly lower range; check the spoon-drip test — the glaze should fall from a spoon in a slow, ribbon-like stream, not drop in clumps or run like water.

Mirror Glaze Basics

A mirror glaze (glacage miroir) adds gelatin to a glaze base — typically white chocolate or a sugar-cocoa mixture — along with glucose syrup and, for colored versions, food-safe coloring. Gelatin provides the characteristic mirror-like sheen and a slight cling that dark ganache alone cannot achieve.

Key steps for mirror glaze:

1. Bloom gelatin sheets in cold water until fully softened (follow the sheet weight indicated in your formula).

2. Heat cream, glucose, and sugar to a gentle boil; remove from heat.

3. Squeeze excess water from gelatin and stir into the hot mixture until dissolved.

4. Pour over chopped white couverture; let stand briefly, then blend with an immersion blender held below the surface to avoid incorporating air bubbles.

5. Add coloring if desired; strain through a fine-mesh sieve.

6. Cool to pouring temperature (~86–95 °F / 30–35 °C) before using.

Air bubbles are the enemy of a mirror finish. Immersion blend with the blender head submerged, and allow the glaze to rest so bubbles can rise before pouring.

Glazing an Entremet Cake

The cake or mousse round must be fully frozen or deeply chilled before glazing. A cold surface causes the glaze to set on contact, locking in a smooth coat. Room-temperature cakes allow glaze to slide off before setting.

Setup: Place the chilled cake on a wire rack set over a sheet pan lined with parchment or plastic wrap — this catches all drips cleanly, and excess glaze can be scraped up and reused if uncontaminated.

Pouring technique: Starting from the center of the cake, pour in a slow, steady stream and move outward in a spiral, letting glaze flow naturally over the edges. Pour enough to coat in one pass — going back over a setting glaze creates visible marks. Do not spread with a spatula.

Finishing: Let drips stop, then slide a palette knife or offset spatula under the wire rack and transfer the cake to a cake board in one confident movement. Wipe or trim any long drips from the base with a warm palette knife.

Safety in the Lab

• Use heat-resistant gloves or dry towels when handling hot saucepans; steam from boiling cream causes burns.
• Keep work surfaces dry to prevent slips; wipe spills immediately.
• The immersion blender blade is sharp — unplug before cleaning or moving the blade guard.
• Use a calibrated digital thermometer; do not guess at temperatures.
• Acetate strips in contact with food must be food-safe; never substitute non-food-grade plastic.
• Keep long hair tied back and wear a clean apron and non-slip footwear in the lab.