Vapor_Eyes
taste buds
I couldn't agree more. You have to take into account the chamber design and material which can introduce small amounts of conduction. If you just turn on the Grasshopper and let it sit, it won't cook your material. However, once you start to take the first hit the chamber walls heat up which adds a small amount of conduction to the process. Taking one hit at a time will lessen this effect but it is still there. Taking multiple hits in a row will increase this effect and allow for a little more extraction from your material.100% convection heater, but if the chamber is at equilibrium with the heater (as would be ideal for the hopper) there is faster transfer of energy from the side walls to the herb than there is from the air to the herb. This effects the profile of the vape.
There is also radiant heat to consider. This is mostly affected by the distance from the heater to the chamber.
Most vapes that are 100% convection in theory are probably more like 90-95% convection. A log vape, for example, has the material very close to the heater introducing more radiant heat, and the stems are glass, which provide some conduction, or stainless steel which provides extra conduction and slightly bigger hits. Even the Evo will cook an ELB if you leave it in the bamboo for a while.
Being less than 100% convection isn't a bad thing, it gives vapes their unique signature and effects profile. My Sticky Brick vapes are the purest convection I've experienced. The chamber is made of wood which conducts almost no heat to your material. The heat source, which is the butane flame, is also far away from the chamber and above it, introducing little radiant heat.