Bitter

Bitter taste reduces the feeling of slime from mouth and numbs the tongue. Bitter taste also helps in downward movement of Vata. ¹ 

Attributes:

• Is the coldest amongst all the tastes. ²
• Is dry, light. ¹

Potency: Hot Potency ¹

Post-Digestive Taste: Pungent Vipaka

Elements associated:

• Air ¹
• Space ¹

Seasons to consume Bitter Foods ³:

• Spring 
• Autumn 

Relationship with Malas (waste): Helps in retaining waste products. ¹

Categorisation on the basis of digestion: Avidahi (causes no burning during digestion and helps in recovery from loss of consciousness) ¹

Physical Features ²:

• Heals anorexia (an eating disorder resulting in extreme weight loss)
• Detoxify and help in managing obesity ¹
• Good for diabetes patients ¹
• Purifies throat and liver ¹
• Helps in fighting parasites.
• Helpful in skin disorders.
• Useful in fever, nausea.
• Reduces burning sensations.
• Cleanses throat.
• Is easily digested.
• Promotes intelligence. 

Mental Features:

Each of the six tastes produces or enhances a certain emotion when eaten. The emotion associated with bitter taste is grief. 

• Clears the senses and the emotions. ²

If it is consumed in excess, it becomes a cause of:

• Reduction in tissues, plasma, blood, bone marrow and sperm count ¹
• Has the most negative effect on heart. ²
• Dryness of mouth ¹
• Reduction of strength ¹

Foods that are bitter but don't have negative effects associated with those:

• Tinospora (guduci) ¹
• Pointed gourd ¹

References:

1. A Practical Approach To The Science of Ayurveda - Acharya Balakrishna
2. The Ayurvedic Encyclopedia - Natural secrets to healing, prevention and longevity - Swami Sada Shiva Tirtha
3. Bhojanakuthalam - Pg 484