Cold Infusion

Most people instinctively reach for hot water when steeping herbs. Ayurveda, however, recognised long ago that heat can destroy the very qualities you want to preserve in certain plants. That insight gave rise to Hima (cold infusion) -- a preparation made by soaking herbs in unheated water over an extended period.

In a cold infusion, powdered or coarsely crushed herbs are mixed with water at room temperature and left to stand, typically overnight. The water slowly draws out the herb's water-soluble constituents without the volatility changes that boiling introduces.

Classical Ayurvedic texts list Hima as one of the five foundational methods of herbal preparation (Pancha Kashaya). It is the preparation of choice when the intended herbs have cooling, demulcent, or delicate aromatic properties that heat would diminish.

Low-Temperature Extraction

The defining feature of Hima is that no heat is applied. Room-temperature or cool water is used throughout. This preserves volatile aromatic compounds and heat-sensitive constituents that would otherwise be altered or lost during boiling.

Extended Contact Time

Because cold water extracts slowly, a Hima preparation typically requires several hours of soaking -- often overnight. The longer contact time compensates for the absence of heat, allowing the water to absorb the herb's active constituents at a gentler pace.

Cooling Therapeutic Qualities

Hima is specifically suited to herbs with cooling (Sheeta) properties. Classical Ayurveda prescribes cold infusion when the therapeutic goal involves reducing heat, calming inflammation, or supporting conditions aggravated by excess Pitta.

Part of the Five Core Preparations

Hima is the mildest of the five classical extraction methods (Pancha Kashaya). It sits at the "cold" end of the spectrum, with decoction (Kashaya) at the "hot" end, and each of the other methods representing progressively more intensive processing in between.

Preparing a Hima is simple but requires planning ahead. The herb -- usually in coarsely powdered or crushed form -- is measured and placed in an earthen or glass vessel. Clean, room-temperature water is added and the vessel is left undisturbed, typically covered, for six to twelve hours or overnight.

In the morning, the liquid is gently strained. The resulting infusion is consumed soon after straining, ideally at room temperature. Unlike a decoction, a Hima is not heated or concentrated, so it is a lighter, less intense preparation.

Ayurvedic practitioners use cold infusion most often in the context of heat-aggravated conditions -- fever management, burning sensations, or situations where the patient's constitution is already hot and dry. Herbs frequently prepared as Hima include those with sweet, cooling, or demulcent qualities.

The preparation is also used when a patient cannot tolerate warm or stimulating medicines, as Hima is among the gentlest of the five classical extraction methods. Its mildness makes it appropriate for sensitive individuals or as a complementary preparation alongside stronger therapeutic forms.

• Five Methods of Herbal Preparation (Pancha Kashaya) -- Hima is the mildest of the five classical extraction methods. Understanding all five shows how cold infusion relates to and differs from decoction, hot infusion, paste, and fresh juice.
• Herbal Formulation (Yoga Kalpana) -- Classical formulas specify which extraction method to use. A Hima is one possible form a complete formulation may take.
• Anupana (Carrier Substances) -- Like other preparations, a cold infusion may be prescribed alongside a specific carrier substance to direct its action.