Malt syrup is a thick, dark sweetener made from sprouted barley that has been dried, roasted, and concentrated into a viscous liquid. It has a distinctive flavor, less sweet than honey or table sugar, with rich caramel and slightly nutty notes. You’ll find it in bagel shops, breweries, and bakeries, where it serves purposes that go beyond simple sweetening.
How Malt Syrup Is Made
The process starts with malting: barley grains are soaked in water and allowed to sprout. Sprouting activates enzymes inside the grain that convert its starches into simpler sugars, primarily maltose. Once the grain reaches optimal growth, it’s dried and roasted to develop color and flavor. The roasted malt is then mashed (soaked in hot water) to extract those sugars into a liquid, which is filtered and slowly evaporated down into thick syrup.
The roasting stage is where much of the flavor develops. Lighter roasts produce a milder, more subtly sweet syrup, while darker roasts create deeper caramel and toasted notes. Those roasted flavors come from the same chemical reactions that brown bread crusts and caramelize sugar: interactions between sugars and amino acids that generate dozens of flavor compounds.
Diastatic vs. Non-Diastatic Malt
This distinction matters more than most people realize, especially if you’re baking bread. Diastatic malt contains an active enzyme that breaks down flour starch into sugars that yeast can eat. Adding it to dough speeds up fermentation, giving you a faster, more vigorous rise. Non-diastatic malt has been heat-treated to disable that enzyme, so it contributes sweetness, color, and flavor without affecting how your dough rises.
Barley malt syrup sold in jars at grocery stores is almost always non-diastatic. Diastatic malt is more commonly sold as a powder and used in very small amounts. King Arthur Baking recommends starting at roughly 0.2% of the flour’s weight if you’re adding diastatic malt to a recipe that doesn’t call for it, then adjusting in small increments. Too much will make your dough sticky and overly soft because the enzyme breaks down too much starch.
Non-diastatic malt syrup is more forgiving. It boosts browning and adds its characteristic malty sweetness without the risk of over-fermenting your dough.
What It’s Used For
Malt syrup is essential to a few iconic foods. Traditional New York bagels get their glossy, slightly sweet crust from a malt syrup bath before baking. Pretzels rely on it for similar reasons. In both cases, the sugars in the syrup promote deep browning and add a layer of flavor you can’t replicate with plain sugar.
Brewers have used malted barley as their primary sugar source for centuries. The syrup form is popular with home brewers because it’s a convenient, pre-processed way to get fermentable sugars into a batch without doing a full grain mash. In baking beyond bagels and pretzels, malt syrup shows up in whole grain breads, granola, and cookies where you want a complex, less aggressively sweet flavor. It pairs especially well with dark flours like rye and whole wheat.
Some people also use it as a table sweetener, drizzled over oatmeal or stirred into warm drinks. Its sweetness is noticeably lower than honey, maple syrup, or table sugar, which makes it a useful option when you want depth of flavor without overpowering sweetness.
Nutritional Profile
Malt syrup is still a concentrated sweetener, so it’s calorie-dense and mostly carbohydrates. But compared to refined sugar, it brings more to the table nutritionally. Per 100 grams, it contains meaningful amounts of several B vitamins: about 8 mg of niacin (roughly half the daily value), 0.5 mg of vitamin B6 (about 38% of daily needs), and 0.39 mg of riboflavin (30% of daily needs). It also provides 72 mg of magnesium and 320 mg of potassium.
It contains small but notable amounts of amino acids, including tryptophan, threonine, and valine, which is unusual for a sweetener. None of these nutrients are present in amounts that would make malt syrup a health food, but they do make it a more nutritionally interesting choice than white sugar or corn syrup if you’re using a sweetener anyway.
How It Compares to Other Sweeteners
Malt syrup sits at the low end of the sweetness scale among common liquid sweeteners. It’s roughly half as sweet as white sugar, which means you’ll need more of it to achieve the same level of sweetness in a recipe. Its flavor is distinctly malty and almost savory, with roasted, caramelized undertones that set it apart from the clean sweetness of honey or the butterscotch quality of maple syrup.
Its thick, sticky texture is comparable to molasses, and the two share some flavor overlap, though molasses tends to be more bitter and mineral-heavy. Brown rice syrup has a similar consistency but a more neutral taste. Honey is thinner and significantly sweeter.
Substitutes and Ratios
If you can’t find malt syrup, blackstrap molasses is the closest swap. Use a 1:1 ratio: half a cup of molasses for half a cup of malt syrup. The result will be somewhat sweeter and richer, with a more pronounced bitterness, but it works well in bread recipes and dark baked goods.
Brown rice syrup and maple syrup are both sweeter alternatives that can be substituted at a 1:1 ratio as a starting point, though you may want to reduce the amount slightly to avoid over-sweetening. Honey also works at a 1:1 ratio but is stickier to work with and will change the flavor profile more noticeably. Agave falls somewhere in the middle for sweetness. With any substitute, expect some experimentation to get the flavor and texture right for your specific recipe, since none of these replicate malt syrup’s distinctive roasted, grain-forward character.
Buying and Storing Malt Syrup
Look for barley malt syrup in the natural foods aisle of grocery stores or online. Eden Foods and Wholesome are two widely available brands. It’s typically sold in glass jars and can be extremely thick at room temperature, almost like cold honey. Warming the jar briefly in hot water makes it much easier to pour and measure.
Stored in a cool, dark place with the lid tightly sealed, malt syrup keeps for well over a year. It doesn’t need refrigeration, though refrigerating it will make it even thicker and harder to work with. If you notice any off smells or mold, discard it, but spoilage is rare given its low moisture content and high sugar concentration.