Add some dextrose to your starters and the yeast should take off faster and have thicker cell walls.
Wrong, and wrong in a way that will harm the yeast.
If you feed yeast on simple sugars it gets lazy with regard to higher sugars, these are exactly the sugars we want the yeast to consume to get the beer to fully attenuate. About the worst possible time to feed yeast on simple sugars is during the reproductive phase.
There are a bunch of other reasons to culture yeast on wort, including sterol precursors, protein, glycogen reserves... All of which we want to maximise in a starter that is going to be sent of to work hard in a wort. None of these are supplied by "sugars" but just looking at sugar metabolism.
Yeast will pretty much tackle sugars in order of size, so monosaccharides first (glucose, fructose), then disaccharides (Maltose and Sucrose) then higher sugars some but not all of the trisaccharide's.
Yeasts approach to Maltose and Sucrose is quite different, it takes Maltose into the cell and breaks it down, it cant import Sucrose so it produces Invertase enzyme which is pushed into solution (and stays there for good (or bad)), it then breaks down the Sucrose into Fructose and Glucose which are taken up from solution by the yeast. Yeast will preferentially produce invertase even over other reproductive pathways, which would make using Sucrose in a starter even worse than Glucose/Dextrose (same thing).
I suspect (cant prove) that this treatment of sucrose is strongly linked to the traditional "Kit Twang" people talk about.
Hoppy2B, you are getting to be notorious for posting complete crap in very authoritative terms!
When you don't know WTF you are talking about try asking a question.
I would agree that a little yeast nutrient (a complex one not just DAP) and/or a little zinc wouldn't go astray, but if you want to make plenty of good healthy yeast, avoid sugars and use wort (DME/LME same thing).
Mark
