Free herb drying calculator. Enter fresh herb weight to find the dried yield and the drying trays you need for a home herb harvest.
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Enter the fresh herb weight in grams. This herb drying calculator estimates dried yield at 20 percent of fresh weight, because fresh herbs are mostly water, and estimates drying trays at one tray per 500 grams of fresh herbs. The per herb table below adjusts expectations by herb type and method: air drying takes days to weeks, while a dehydrator takes hours. Always use the crumble test before storing, because herbs that feel dry on the outside can still hold moisture inside.
Fresh to dried herb conversion follows a well known spoon rule: 3 parts fresh herb equals 1 part dried herb, so 3 tablespoons of fresh herb replace 1 tablespoon of dried herb, and 1 tablespoon of fresh herb replaces 1 teaspoon of dried herb. By weight, fresh herb weight to dried weight conversion is different: fresh herbs are about 70 to 90 percent water, so dried weight is roughly 10 to 30 percent of fresh weight. This calculator uses 20 percent as a middle planning figure, which means 500 grams of fresh herbs gives about 100 grams dried, and 100g fresh herbs gives about 20 grams dried.
Air drying herbs time by herb type varies a lot. Tender leafy herbs such as basil, mint, parsley and cilantro dry faster than woody herbs such as rosemary, thyme and sage, but they also mould more easily if air flow is poor. How long to dry basil rosemary thyme in a dehydrator is a common question: at 95 to 115 degrees Fahrenheit, most herbs take 1 to 4 hours in a dehydrator, with basil at the fast end and rosemary at the slow end. Woody herbs may take 4 to 8 hours at the lowest dehydrator setting, so check often rather than trusting a single time.
How long to dry herbs depends on the method. Air drying takes 5 to 10 days in good conditions, 1 to 2 weeks in many homes, and up to 4 weeks in humidity, so it suits small bundles hung in a dry airy room. Oven drying at the lowest setting takes about 1 to 4 hours, dehydrator drying takes 1 to 4 hours at 95 to 115 degrees Fahrenheit, and microwave drying takes 1 to 3 minutes in 30 second bursts. Herb dehydrator time and temperature matter most for flavour: hotter than 115 degrees Fahrenheit dries faster but loses aroma, so stay low and slow.
How many dehydrator trays for fresh herbs is the planning question this calculator answers directly: it allows 500 grams of fresh herbs per tray, so 500 grams needs 1 tray and 1,200 grams needs 3 trays. Spread herbs in a single layer with space between leaves, because overlapping leaves trap moisture and invite mould. If your dehydrator trays are small, count trays by area instead: fill each tray loosely, never packed, and dry in batches rather than overloading one tray.
How do you know when herbs are fully dry? Leaves should crumble easily between your fingers and stems should snap cleanly instead of bending. That crumble test is more reliable than time alone, because humidity, herb type and bundle size all change drying time. If leaves feel leathery or stems bend, keep drying: storing damp herbs causes mould and ruins the whole jar. Test the thickest leaves and stems, not just the driest ones on the outside.
How long do dried herbs last? At peak flavour, dried herbs last about 6 to 12 months when stored airtight, dark and cool, while intact dried leaves can stay usable for 2 to 3 years with fading flavour. Store in labelled glass jars away from heat and light, and crush leaves only when you cook, because whole leaves keep flavour longer. Discard any jar that smells musty or shows mould, and never try to save mouldy herbs.
For 500 grams of fresh herbs, this calculator gives 100 grams of dried herbs and 1 drying tray. For 1,200 grams, it gives 240 grams dried and 3 trays, because 1,200 divided by 500 rounds up to 3. In spoon terms, that 100 grams of dried herb is far more than a recipe needs at once, so a single harvest can season many meals if it is dried and stored well.
How much dried herb equals fresh in cooking? Use the 3 to 1 rule: use one third as much dried herb as fresh herb in a recipe, so 1 tablespoon of fresh herb becomes 1 teaspoon of dried herb. Dried herbs suit simmered dishes, soups and sauces, where they have time to release flavour, while fresh herbs suit quick dishes and finishing. Add dried herbs early in cooking and fresh herbs near the end for the best flavour from both.
Use the 3 to 1 rule: 3 parts fresh herb equals 1 part dried herb, so 1 tablespoon of fresh herb replaces 1 teaspoon of dried herb. By weight, dried yield is about 10 to 30 percent of fresh weight, and this calculator uses 20 percent as a planning figure.
Air drying takes 5 to 10 days in good conditions and up to 2 to 4 weeks in humidity, oven drying takes 1 to 4 hours, dehydrator drying takes 1 to 4 hours, and microwave drying takes 1 to 3 minutes. Herb type, moisture, quantity, temperature and humidity all change the time.
Dry herbs at 95 to 115 degrees Fahrenheit in a dehydrator or at the lowest oven setting. Higher temperatures dry faster but lose flavour and aroma, so keep the temperature low and check the crumble test rather than raising the heat.
Leaves should crumble easily between your fingers and stems should snap instead of bending. If leaves feel leathery or stems bend, keep drying, because storing damp herbs causes mould.
One third as much dried herb as fresh herb: 3 teaspoons of fresh herb equal 1 teaspoon of dried herb, and 1 tablespoon of fresh herb equals 1 teaspoon of dried herb. Ground herbs are stronger still, so use even less.
No. Tender herbs such as basil, mint and parsley dry faster but mould more easily, while woody herbs such as rosemary, thyme and sage dry more slowly and keep flavour longer. Per herb ratios also vary: basil and parsley are often 2 to 1, most herbs are 3 to 1, and rosemary and sage can be 4 to 1 by spoon measure.
Dried herbs keep peak flavour for about 6 to 12 months in an airtight, dark, cool jar, and intact leaves can stay usable for 2 to 3 years with fading flavour. Label jars with the herb and date, and crush leaves only when cooking.
Yes, if the herbs are fresh and undamaged. Wash and dry them gently first, remove any damaged leaves, and dry them the same way as garden herbs. Herbs that are already wilting or damp are more likely to mould, so use the freshest bunches you can find.