Sugar swaps syrup
Sugar-Free Simple Syrup (Allulose)
Allulose and water: pours, sweetens and stays liquid in the fridge. No crystals.
- 5 min total
- 1½ cups350 ml
- Keeps 3 weeks
Quick answer
The best sugar-free simple syrup is made with allulose: warm 1 cup allulose with 1 cup water until clear, cool and refrigerate. Unlike erythritol, allulose doesn't recrystallize in the fridge, and it's about 70% as sweet as sugar, so use a little more.
Most keto syrups fail the same way: they look perfect warm, then turn into a jar of crystals overnight. That's erythritol, which barely dissolves in cold water. Allulose behaves much more like real sugar: it dissolves easily and stays liquid.
Allulose is about 70% as sweet as sugar. Use roughly a third more syrup than a recipe calls for, or add a few drops of pure monk fruit extract to bring it up to full sweetness.
Tastescleanlightly sweetno aftertaste
The recipe
Sugar-Free Simple Syrup (Allulose)
Ingredients for 1½ cups350 ml
You’ll need: allulose, monk fruit sweetener, small saucepan, kitchen scale, pump bottle, swing-top bottleallulose, monk fruit sweetener, small saucepan, kitchen scale, pump bottle, swing-top bottle
Method
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Combine
Add the allulose to a small saucepan. If using xanthan gum, whisk it into the dry allulose first so it can't clump, then pour in the water.
1 cup200 g granulated allulose1 cup240 ml water
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Dissolve gently
Warm over medium-low heat, stirring, until completely clear, 2–3 minutes. Don't boil: allulose browns and turns bitter at lower temperatures than sugar.
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Adjust sweetness
Take it off the heat and let it cool. Add monk fruit drops a few at a time if you want it as sweet as regular simple syrup.
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Bottle
Funnel into a clean bottle and refrigerate. Shake before using if you added xanthan.
Storage. Keeps about 3 weeks sealed in the fridge. If a few crystals ever form, warm the bottle in hot water and shake. Discard if cloudy, slimy or sour-smelling.
How to use it
Iced coffee & cold brew
2 tbsp (30 ml) per 12 oz glass. It dissolves instantly, with no gritty sweetener at the bottom.
Low-sugar margarita
1 oz (30 ml) with 2 oz (60 ml) blanco tequila and 1 oz (30 ml) fresh lime. Shake, serve over ice with a salt rim.
Whiskey Sour
1 oz (30 ml) with 2 oz (60 ml) bourbon and ¾ oz (22 ml) lemon. Shake hard.
Mojito
1 oz (30 ml) with 8 mint leaves, 1 oz (30 ml) lime and 2 oz (60 ml) white rum; top with soda.
Sugar-free lemonade
1⅓ parts syrup, 1 part fresh lemon juice, 4 parts cold water.
Gear for this recipe
Glass Coffee Syrup Dispensers with Pumps (16.9 oz, set of 2)
A pump gives the same dose every press, so every latte tastes the same. Glass washes clean between flavors.
Best for Home coffee bars
Escali Primo Digital Kitchen Scale (11 lb)
Best for Exact ratios, every batch
Otis Classic 16 oz Swing-Top Glass Bottles (6-pack)
Best for Storing and gifting any syrup
Wholesome Allulose Zero-Calorie Sweetener
Best for Sugar-free and keto syrups
More gear for this recipe (2)
Lakanto Classic Monk Fruit Sweetener (1:1 Sugar Substitute)
Best for Sugar-free syrups
Cuisinart Chef's Classic 1.5 qt Stainless Saucepan with Lid
Best for Every stovetop syrup
Tips for the best batch
- Allulose is about 70% as sweet as sugar. Use 1 oz (30 ml) where a recipe calls for ¾ oz (22 ml) simple syrup, or boost it with monk fruit.
- Avoid erythritol for syrups. Only around 13 g dissolves in 100 ml of cold water, so it crystallizes in the fridge. Many 'monk fruit sweeteners' are mostly erythritol, so check the label.
- Keep it at 1:1. Richer allulose syrups (2:1) can grow crystals in the fridge.
- Start with a couple of tablespoons a day. Large amounts of allulose can cause bloating in some people.
- Xanthan gum adds the body of a coffee-shop syrup, but too much turns it slimy. A scant ⅛ teaspoon per batch is plenty.
Variations
Allulose + monk fruit (sugar-sweet)
Add pure monk fruit extract until it tastes as sweet as classic simple syrup. Then you can swap it measure-for-measure in any recipe.
Erythritol version (if you must)
Use half as much erythritol as water (100 g to 200 ml), dissolve warm, and use within a week. Expect some crystals; rewarm to dissolve.
Sugar-free vanilla
Steep a split vanilla bean in the warm syrup for 30 minutes, or add 1 tbsp vanilla extract once cool.
Sugar-free flavored coffee syrups
Use this base in our caramel, pumpkin spice or gingerbread recipes. Keep the heat low and skip true caramelizing.
Questions people ask
What's the best sweetener for sugar-free simple syrup?
Allulose. It dissolves easily, has a clean sugar-like taste and stays liquid in the fridge. Erythritol tends to crystallize, and pure monk fruit is too concentrated to make a syrup by itself.
Why does my sugar-free syrup crystallize?
It almost certainly contains erythritol, which has low solubility in cold water. Switch to allulose, or use half as much erythritol and accept a shorter shelf life.
Can I make simple syrup with monk fruit sweetener?
Check the label. Most granulated monk fruit sweeteners are mainly erythritol and will crystallize. Pure liquid monk fruit extract works best as a few drops added to an allulose syrup.
Is allulose syrup keto-friendly?
Allulose is widely used on keto diets because the body doesn't metabolize it like sugar and it has very few calories. The FDA excludes it from total and added sugars on US labels.
How long does sugar-free simple syrup last?
About 3 weeks in the fridge in a clean, sealed bottle. Erythritol versions are best used within a week.
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