Regarding your need for a warm beverage to drink while you are working, milk is the best. Take hot milk with little sugar, stir it very nicely, and drink it when it is warm sufficiently, tolerable by you, and with bubbles on the surface. That is the best hot beverage available in the world. You can also prepare some halevah. That is also very nice for a cold country. Add to it some raisins, almonds, etc.
Letter to Sivananda, 4 May, 1969