How to Grind Whole or Sliced Herbs into Powder (Coffee/Spice Grinder Guide)

Turn whole or sliced herbs into smooth, recipe-ready powder with a simple blade coffee or spice grinder. This guide covers tools, prep, exact steps, sieve tips, cleanup, storage, and common pitfalls—so you get fine, consistent powder every time.

Why grind your own herbs?

Freshness & potency: You control when it’s ground, how fine it gets, and how it’s stored.

Versatility: Powder mixes into teas, decoctions, capsules, smoothies, seasoning blends, and topical recipes.

Savings: Whole or sliced herbs in bulk are often more cost-effective than pre-powdered.

What you’ll need

Dried herb (whole or sliced; fully dry is essential)

Blade-style coffee/spice grinder (dedicated to herbs)

Fine-mesh sieve/tea strainer (60–80 mesh is ideal for capsule-fine; kitchen strainers also work)

Airtight glass jars + labels (food-safe desiccant optional)

Optional: mask (herb dust), rolling pin/mallet (to pre-break slices), kitchen scale, dehydrator

Coffee grinder vs. spice grinder vs. burr grinder

Bottom line: Use a blade grinder for herbs. Burr grinders are for coffee.

Prep: set yourself up for success

1. Confirm dryness (“snap test”)

   • If a stem or root bends instead of snapping, dehydrate 30–90 min at low heat (95–115°F / 35–46°C).

2. Right size in = right size out

   • Leaves/flowers: crumble by hand first.

   • Sliced roots/barks: place in a clean bag and pre-break with a rolling pin.

   • Oily seeds/berries: freeze 10–15 min so they powder instead of smearing.

3. Dedicate your grinder

   • Herbal aromas linger. Keep a separate grinder for herbs (not your morning coffee).

Step-by-step: how to grind herbs into powder

Load half-full

Overfilling causes uneven grind and heat buildup.

Pulse in short bursts

5–10 seconds on, brief rest; repeat. This keeps powder cool and protects aroma.

Shake between pulses

Tilt or swirl the grinder so coarse bits meet the blade.

Sieve & re-grind

Pour through a fine sieve. Keep the fine powder; return coarse bits for 1–2 more passes.

Cool & de-static

Let powder sit 5–10 minutes before jarring to reduce clumping.

Jar, label, store

Airtight glass, cool, dark, dry. Label with name + date + lot if you track batches.

Pro tip: Two quick grind-and-sieve cycles beat one long grind—faster, cooler, finer.

How fine should it be?

Mesh guide (approximate):

Kitchen strainer ≈ 20–40 mesh (good for tea).

Fine tea/screen sieve ≈ 60–80 mesh (capsule-fine).

Herb-by-herb pointers

Leaves & flowers (e.g., mulberry leaf, mint, chrysanthemum): grind fast—short pulses only.

Roots & barks (e.g., licorice, hu zhang/japanese knotweed, cinnamon, dan shen): pre-break; expect 2–3 passes + sieve.

Seeds & fruits (e.g., fennel, coriander, pepper): freeze briefly first; grind tiny batches to avoid pasting.

Resins & very oily spices: freeze hard, pulse quickly, clean immediately afterward.

Grindability index (quick cheat sheet)

*Passes = grind → sieve → re-grind coarse fraction.

Yield & density (rule-of-thumb)

1 cup broken slices → ~⅓–½ cup fine powder (varies by herb & cut).

For precision, weigh your powder (kitchen scale). If you’ll make capsules, weigh one filled capsule to estimate mg/cap for your specific grind.

Storage & shelf life

Airtight glass; keep cool, dark, dry.

Fill jars to minimize air space; add a food-safe desiccant in humid climates.

Most powders are best within 24–36 months if color and aroma remain vibrant.

Cleaning the grinder (no lingering smells)

Brush out residue.

Grind 1–2 tbsp dry white rice; discard.

Wipe cup & lid with a dry, lint-free cloth. (If removable parts are washable, dry completely before use.)

Troubleshooting

Clumping/sticking: Herb not dry → dehydrate briefly; freeze oily seeds; let powder cool before jarring.

Stringy bits in powder: Sieve and re-grind the coarse fraction.

Burnt/bitter smell: Overheated—use smaller loads and shorter pulses.

Grinder stalls: Too full or pieces too large—empty halfway, pre-break slices.

Capsule basics (optional)

Common size “00” capsules hold roughly 600–800 mg, depending on powder density.

Fill a few capsules, weigh them, and note the average mg/capsule on your label for consistency.

FAQ 

Can I grind fresh herbs?
Dry them completely first—moisture causes clumping and shortens shelf life.

Can I use a burr coffee grinder?
No—burrs clog and won’t produce flour-like powder. Use a blade grinder.

Which sieve should I buy?
For capsules and ultra-smooth blends, aim for 60–80 mesh. For tea, many kitchen strainers (20–40 mesh) are fine.

How do I stop powder from clumping later?
Store airtight, cool, and dry. Let powder cool 5–10 minutes before jarring; consider a food-safe desiccant.

Is the metal grinder's heat a problem?
Heat can dull aroma. Short pulses with rests prevent overheating.

How fine should tea powder be?
Personal preference. Coarser powder strains easier; finer powder extracts faster but may leave sediment (use a paper filter if you want a clear cup).

Safety & compliance

Label clearly (herb name, date, lot if applicable). Keep away from children and pets.

Some herbs may be potent or interact with medications; consult a qualified professional—especially if you’re pregnant, nursing, or managing a condition.