The process of digestion (ahar pachan) is divided in three stages, which collectively is called awastha paka and can be divided in the following :-

» Amavstha (Madhuravastha) Paka
» Pachymanavastha (Amlavstha) Paka
» Pakavstha (Katuavstha) Paka

Amavstha (Madhuravstha) Paka
This first stage of digestion occurs in the stomach (amashaya). During the process the ingested food is liquefied and madhura rasa develops which dominates other rasas. The semi digested food gets madhurawastha. Even the ingested chilly will also have stage of digestion.

The Kledaka Kapha present in the stomach liquefies and mixes the ingested food. The Sharirik Kapha also is generated in this phase of digestion. The quantum of the kapha produced depends on the rasa of ingested food. Kapha aggravating rasa (Madhur, amla & lavan) and generates large quantum of kapha where as kapha diminishing rasa generate less quantum of kapha dosha Due to this reason it is said that kapha Dosha is aggravated soon after eating food. The sign & symptoms of Kapha Roga (disease related to kapha dosha) are aggravated at this stage.

Pachyamavstha (Amlavstha) Paka
At this stage of digestion the ingested food is partially digested (vidagdha awastha) and the amla rasa (sour taste) arises. The amal rasa dominate sthe other rasa (taste). All these activities of further digestion occurs in the grahani i.e. pitta dhara kala. The main function of Grahani is to Grahan (to take) Dharana (hold on) and Munchan (to release). During the process Grahani receives vidagdha amma (partially digested food).

At this phase of digestion Pachaka Pitta (bile along with pancreatic juice and other digestive enzyme) is released in grahani (duodenum) and grahani performs its function of dharana (hold on) and pachan (digestion) is performed by pachaka pitta. At last the ingested food is digested and separated into Sara (essence) and Kitta (excretory product) part.

During this phase pitta dosha is generated due to amla rasa (sour taste). The quantum of the pitta dosha generated depends on the rasa of ingested food.

Example- If ingested food is chilly then the quantum of pitta will be very high and if the ingested food is sweet than the quantum of pitta dosha is very less.

Pakuavstha (Katuavstha) Paka
This phase of digestion takes place in the large and small intestine (pakvashaya). During this phase the water of the digested food gets absorbed by the help of vata dosha and agni making the food rough and producing kattu in rasa (chilly taste) and generation of vata.

As the rasa changes in different phase of digestion these phase of digestion are called avsthapaka. At the end of the digestion the digested food have their original rasa which is in accordance with the rasa of the ingested food. This is called as Nistha paka or Vipaka.

Vipaka is classified into three groups i.e. Madhur, Amla and Katu depending on the functions of six rasa that is categorized into three types and named accordingly.

Madhur rasa & Lavan rasa have Madhura Vipaka, Amla rasa have amla vipaka and Katu, Tikta & Kashaya rasa have Katu vipaka.