A teapot is used to cook tea leaves and prepare liquid essence of tea from them. At the mouth of the teapot is a strainer that prevents the tea leaves from pouring freely into the cup. When the tea leaves sink to the bottom of the teapot and there is clear tea essence above them, one may certainly pour the clear essence into a cup. But when the tea leaves and the water are mixed, some say that one may not pour the essence through the mouth of the teapot because the strainer separates the liquid essence from the tea leaves. Others permit this. Since it is easy to add hot water (from a kli sheni) to the teapot, ensuring that a large volume of liquid is not mixed with the essence, it is preferable to do this and thus avoid risking a possible prohibition of Borer. When it is impossible to add water, be-di’avad pouring out the essence through the strainer is permitted.
One may make tea by putting a tea bag into hot water (in a kli shlishi, as explained above in 10:8). However, when lifting the tea bag from the water, it is proper to take care not to hold it over the cup to allow the tea bag to drip the last few drops into it. This is because some maintain that the tea bag, which keeps the tea leaves from getting loose, is considered a utensil for straining, in which case holding it up would be considered separating the tea essence from the leaves using a utensil (see section 7). Instead, one should remove the tea bag from the cup and immediately put it in the garbage or into another cup. Some are stringent and lift the tea bag using a spoon, thus removing some tea along with the tea bag (see SSK 3:64).