Recently I found out the wonders of cold brewing your herbal teas and I thought I would share. Using the same amount of herb and liquid you would as hot brewing, simply let the herb(s) sit in cold or room temperature water with a cover over it. It takes a bit longer but helps to maintain the nutrients that are present in the herbs.
If your making the tea to help with congestion you should still hot brew it. However it aides in teas that are being made for upset stomach such as mint and chamomile. If taking the tea for weight loss or its nutritive benefits, it should be cold brewed. Cooking herbs (like cooking vegetables) can remove some nutrients like vitamin C.
It is also beneficial to saving energy. Not only are you saving on cooking it, but it keeps your house cooler in the summer. If your on the go you can take a bottle of water and a tea bag with you. If it is not bagged you can make one using a coffee filter and twist tie. Just drop the bag in your water bottle and let it sit while your out. On the go tea without having to buy instant! :D