Could i use vermiculite instead of perlite?

I would think so...as long as its new vermiculite and not older that has started to break down. You will get real roots rather than water roots btw,by using a media. No transplant shock into potting soils afterwards.

Twist the top off you say? Seems odd that it can be detached that easy. I'll have to buy one and try it

Easy as pie Larry. When you peel off the lower leaves you will see root bumps ready to break open in soil.

Done it, just like that!

Pineapple. Then a quick twist

Proto roots!

Do I plant straight away or allow to dry?

I think it is better to let the top dry out for a few days (not more than a week) - otherwise it can develop rot. Once you plant it in soil, the soil should be kept moist but not wet. I use cactus potting soil, which drains well and helps prevent rot.

I have several pineapple plants in my back yard, and I got this fruit last December - I picked it a couple of months later, however.

That is so cool Lars. Shame that could never happen here! Soil I use is limited to multi purpose compost but I mix vermiculite with it. I adjust the ratio depending on the plant. Soil wise I'd treat a pineapple like I would a succulent