Lao Cha Tou literally means "old tea nugget." This tea is formed during the pu-erh fermentation process in which tea is piled and kept moist and covered to promote fermentation. During the fermentation, the temparature in the tea piles increase gradually, in order to allow tea leaves to ferment based on the interactions of their interior enzyme thus creating ripe pu-erh tea. During the entire process, workers need to stir and turn over the teas every few days in order to gain equal fermentation and heat distribution to prevent over fermenting the tea leaves at the bottom of the pile where it is hottest. During the fermentation and stirring, some of the tea leaves will excrete their natural pectins and soluble sugar causing them to bond together. After the fermentation is complete, the workers sieve these nuggets out and set them aside to create the "old tea nugget" tea. So the nugget tea is a much more fermented tea compared to the usual ripe pu-erh tea. In other words, this is the reason that it has a greater thickness and mellowness in the tea soup and infusability is better than the other ripe pu-erh teas.