Two different gynostemma teas taste completely different, why

As posted in comments by members of the community (and adding my own), several tips can help you get good warm tea in your thermos at wake-up:

• Choose loose leaves instead of tea bags to avoid tea dust that would overinfuse your tea in the thermos. The small amount there is in tea bags, is heavy enough to sink to the bottom very quickly, so if you pour the tea slowly into your thermos, you can discard it. You can also rinse the tea before brewing with cold water to help expel any excess dust, or (as done in many tea-drinking countries) throw out the first cup of tea made with new tea leaves.

• If you're just using tea bags, why not just keep the thermos bedside and then toss the tea bag in in the morning?

• You could try heating cold-infused and strained tea in the evening and put it into the thermos; it has a brewing time of 8 to 12 hours, so you'd have to start this around noon. If you have a microwave close enough to your bed, you could also use cold infusion to make your tea during the night and then give it a blast in the microwave in the morning.

I've been drinking loose-leaf tea at work for many years now, and have gone through most of these.

• cup with a ceramic or glass strainer.

I've tried both the ceramic type with holes and the glass type with slots. The mesh is never fine enough for me. In addition the holes or slots invariably get packed with leaves and are a pain to clean.

• steel strainers.

If you mean the tea-ball type, I can't comment. But a steel mesh strainer is my absolute favorite. I've been using the same one (pictured below) for years now and have never noticed any off flavors. Easy to clean: just dump out the leaves and give a good rinse, picking or sponging out the occasional stuck leaf.

Not microwaveable, but you don't want to microwave the leaves, anyway. Microwave the cup with water in it (put a stirrer in to avoid superheating the water. Yes, it can happen, and has happened to me), then put the strainer in when it's the right temperature.

• cotton strainers.

I have never used one, so I can't comment authoritatively, but it seems like at the least they'd be harder to clean.

• fillable disposable tea bags.

I hate disposable anything. I tried the type of bag pictured below and they were a pain. They tend to wick tea out of the cup and onto your table.

As for the other gizmos, I think for tea, simpler is better. The above are the only methods I've used, and I find the mesh basket is far and away the most convenient and best solution.