Teabags are usually filled with low tea grades, such as dust and fannings which are smaller pieces of tea… which means more opportunities for the essential oils (what makes tea flavourful and aromatic) to evaporate, leaving the tea dull and stale. Freshness can be a major issue with typical teabags for this reason, especially if they are packed in a paper box with paper wrapping. …. cheap, easy and good enough for your average “milk and sugar” tea drinker…
When you steep loose-leaf tea, it has (or should have) room for tealeaves to absorb water and expand as they infuse. This allows the water to flow through the leaves and extract a wide range of vitamins, minerals, flavours and aromas from the leaves. All the good stuff.
More recently, some tea merchants have decided to adapt the teabag to the tea… opting for higher grades of tea with more sophisticated flavor profiles and aromas…
by putting them into plus-size teabags, “tea pouches” and “tea socks,” as well as “pyramid bags”. World PARTEA has introduced a range of blends in biodegradeable pyramid tea bags for convenience, still using the same 100% natural, chemical free loose leaf tea and herbs.
Some the information above has been extracted from this informative website:
https://www.thespruceeats.com/teabags-vs-loose-leaf-tea-766321