Top or bottom?

It's been a few weeks since my first loaf with my new starter. Christmas has gotten in the way of my baking. The first loaf I made was not bad but not fantastic either. It was kind of a ciabatta, very flat. Good bubbles, good flavor, but underproofed and under baked. I have read some comments about oven temp & will be checking mine before baking again. Was also reading the instructions on making you own sourdough starter. I noticed that it advises throwing out the top of your starter and using the bottom to refresh. I work in a shop that sells wine and craft beers. I have been noticing that a ripe sourdough has a similar aroma to a good wheat beer. Banana and cloves being the dominant aromas in a wheat beer and a similar aroma from the sourdough. Could it be that both are fermented wheat based products? I got to thinking about the beer making process. Top ferment and bottom ferment. After a few beers last night I decided to experiment and refresh two lots of starter; one from the top, one from the bottom. It was a cool night but this morning the aroma of the top starters better and seems the have more bubbles than than the bottom one. Does anyone have any thoughts/ ideas/ knowledge about this? I have also been leaving my starter on the bench without feeding for a few days unt a bloom forms on the top. It still smells sweet and "beery". Then feeding and leaving again. I think I've been throwing out the "best bit". I'll hopefully bake again in next day or so. Need to up the anti and feed again at 12 hours and see if activity increases.