Chocolate syrup carries the flavor; espresso brings the kick.
Bench-tested by the Will It Slush? team · Last revised July 29, 2026
Ingredients
Scale the batch — amounts update live in your units.
- Cold Brew Concentrate295 ml
- Whole Milk355 ml
- Chocolate Syrup (2:1)150 ml
- Water175 ml
Method
- 1.Combine in Slushi on Frappé mode, 45 min.
- 2.Whipped cream + cocoa powder dust.
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Notes from our testing
Chocolate syrup plus milk sugars stack fast — 11 Brix total, not 11 from the syrup.
Milk is not a neutral ingredient. Whole milk contributes around 5 Brix of lactose on its own, so a mocha built from milk plus chocolate syrup plus coffee is carrying sugar from two sources before you add anything deliberate. Treating the syrup as your only sugar is how people end up at 16 Brix wondering why it will not set.
Count the milk. Our build runs about 20 oz of whole milk, 12 oz of chilled strong coffee, and roughly 3 oz of chocolate syrup, landing near 11 Brix total. The milk fat also softens the texture the way coconut fat does in a colada, so aiming at the lower end of the window gives you the right mouthfeel.
Chill the coffee completely before it goes in. Warm liquid is the number one cause of a mocha batch that runs for an hour and never thickens — the machine spends its whole cycle removing heat instead of forming ice.
Skim milk technically freezes better, with less fat interfering, but it makes a thin and slightly icy frappe. Whole milk and a Brix on the low side is the better trade.