In a medium sized saucepan, combine white beans, baking soda and garlic and cover with water. Bring to a boil, reduce to a simmer, and cook for 20-30 minutes.
Strain the beans and garlic and put in a high speed blender.
Add lemon juice, starting with one lemon, and 1 tsp of salt.
Add tahini and olive oil and blend until very smooth.
Drizzle in the ice water gradually and blend until it's the consistency you want.
Taste and add salt and more lemon as needed.
Top with herbs, spices, or like I do with slow roasted tomatoes and serve with pita.