Diet Dr Pepper Slush (Sugar-Free)
Zero-sugar copycat using allulose — slushes without the carbs.
The most-requested recipe from the assistant. Diet sodas don't freeze on their own because they have no sugar — we add allulose (which freezes like sucrose but is keto-friendly) to hit Brix without breaking your macros.
Bench-tested by the Will It Slush? team · Last revised August 3, 2026
Ingredients
Scale the batch — amounts update live in your units.
- Diet Dr Pepper (flat)590 ml
- Allulose70.0 g
- Vanilla extract5 ml
- Sugar (to taste)11.7 g
Method
- 1.Pour Diet Dr Pepper into a bowl and stir to flatten (5 min).
- 2.Whisk in allulose until fully dissolved — this is what lets it slush.
- 3.Add to the Slushi on Slush mode for ~50 min.
- 4.Sugar-free, keto-friendly, ~5 g net carbs per serving.
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Notes from our testing
Zero sugar means zero freezing point depression — this needs allulose, not just diet soda.
Diet Dr Pepper poured straight into the chamber freezes into a solid brown block. This surprises people because it tastes as sweet as the regular version, but sweetness and dissolved mass are different things: aspartame is around 200 times sweeter than sugar, so the actual sugar-equivalent content of the bottle is nearly nothing and the liquid behaves like water.
Allulose is the fix. It is a rare sugar that the body largely does not metabolise, but it is physically present in solution in the same bulk quantities as sucrose, so it depresses the freezing point the way real sugar does. Around 120 g per 64 oz batch brings a diet soda up to roughly 11 Brix-equivalent.
Erythritol is the common substitute and it is a worse choice here. It has a strong cooling effect on the palate that is already amplified by the drink being frozen, and it recrystallises at low temperature, which gives the slush a faintly gritty texture.
Stevia and monk fruit have the same problem as aspartame — intense sweetness, no bulk. If a product's label shows under a gram of carbohydrate per serving, it will not help the freeze. The full comparison is in our sugar-free guide.