In studying Ayurveda’s understanding of the physiological effects of food and drug materials, we rely upon four pillars: rasa (taste), virya (heating or cooling energy), vipaka (post-digestive taste) and prabhava (unique, contrary or anomalous properties of the substance that cannot be accounted for by its rasa, virya or vipaka). Of these, the concepts of rasa, virya and prabhava are fairly straightforward and make sense when explained in non-technical language. Everyone knows what taste is, has experienced the effects of heat and cold, and knows that when we deal with complexities things sometimes do not go as expected. But the concept of vipaka, unique to Ayurveda alone, is somewhat elusive and could well bear further exploration and explanation. This is compounded by the fact that there is a wide diversity of views among different authoritative commentators about the number and types of Vipaka. Some commentators are of the view that every Rasa has its own Vipaka, i.e., that there are six Vipakas corresponding to the six Rasas, while Susrutha holds that there are only two Vipakas viz, sweet and pungent.
After rasa (in foods and medicines) has been assimilated – generally 6 to 8 hours after ingestion - a post digestive ‘taste’ emerges. The six tastes (sweet, sour, salty, pungent, bitter and astringent) are consolidated, leaving three post digestive tastes (vipaka) that remain.
Generally, but with many exceptions:
Sweet and salty rasas have a sweet vipaka;
Sour rasa remains sour, and has a sour vipaka; and
Bitter, pungent, and astringent rasas have a pungent vipaka.
The post digestive taste has a pronounced effect upon one’s doshic constitution. The vipaka of herbs and other medicines, which leave little or no sense impression on the tongue, is more potent and of greater clinical import than the Rasa particularly in long-term usage, precisely the reverse of the case with food materials in which the experience of gustatory taste is a major element.
By way of illustration:
The Sweet and Salty flavors digest into sweet: sweet is nourishing and moistening to the tissues and also has a mildly laxative effect. The cooling and anti-inflammatory nature of sweet make it beneficial to pitta while its wet and anablic (tissue building) properties will increase kapha.
The Sour flavor digests into sour: this will encourage digestion, benefit the liver, increase heat and moisture in the body whilst also calming the nervous system. Its long-term effect is to aggravate pitta and calm vata.
The Pungent, Bitter, and Astringent flavors digest into pungent: its nature is to increase dryness, constipation and gas. These pacify kapha and aggravate vata.
To give an example of how vipaka varies according to the specific energetics of each herb let’s look at two commonly prescribed Peppers.
Both Black Pepper (Piper nigrum) and Long Pepper (Piper longum) are pungent in rasa and heating in virya. Whilst Black Pepper is pungent after digestion and therefore constipating, drying and damaging to the production of reproductive fluids, Long Pepper is sweet post digestively and therefore helps elimination, is moistening and is a beneficial rejuvenative tonic to kapha and an aphrodisiac to the reproductive system.
The question immediately arises, “if both peppers are pungent before vipaka forms, ought not both resolve into pungent vipakas? How is it that Long Pepper, pungent in rasa, evolves into a Sweet vipaka? Aren’t there “rules” that are being broken thereby?
The answer is no, there are no “rules“ being broken. Plants are complex organisms, some continuing as many as 7-8,000 phytochemicals and the phenomena of taste is an extraordinarily complex one. While the rasa has an immediate and localized physiological effect on the digestive system the vipaka has the long-term effect of a food or herb throughout the whole body. Vipaka results from the mixing of agni, the digestive fire, with the particular flavors present and is an extension of the effect of the concatenation of the thousands of phytochemicals giving rise to each particular taste.
Thus, the notion that sweet and salty tastes engender a sweet vipaka, that sour remains sour and that the other rasas evolve into a pungent vipaka is merely a handy rule of thumb, a guideline, to which there are numerous exceptions. Some authorities state that if there is more than one Rasa in a substance, only the strongest of them predominates; others maintain this is not the case. So, in practical terms, the Vipaka cannot always be correctly predicted and relies much upon the actual physiological effects that are noted after digestion, i.e., Katu (Pungent) Vipaka, being light in guna, aggravates Vata, reduces semen and obstructs the passage of stool and urine. Madhura (Sweet) Vipaka, being heavy in guna, aggravates Kapha, promotes semen and helps in proper elimination of stool and urine. Amla (Sour) Vipaka, being light on guna, aggravates Pitta, reduces semen and helps in proper elimination of stool and urine. Thus in the assigning of Vipaka to particular food and medicinal materials, observation of the actual post-digestive effects trumps any systematic categorization.
Article provided by William Courson, BVSA, Dpl. Ayur., C.H. an Ayurvedic Practitioner, faculty member and the College Dean of Institutional Development at Sai Ayurvedic College & Ayurvedic Wellness Center.