and thenchris. wrote:
Be careful using RO water Matt. RO can remove minerals etc that are beneficial to yeast like calcium, various salts etc. It can be a bit of an overkill. I myself use a carbon block filter that cost around $40-50.
Don't know about the hops but is generally accepted that the FAN (free amino nitrogen) levels in malt extract are markedly reduced as a result of their processing and concentration.That's what I've read but I think both malt and hops contain enough minerals to provide what the yeast will need. If your wort had a high percentage of dextrose it might be a problem. It should be simple enough to conduct an experiment.
MattR is certainly correct about not using dextrose (or sucrose) as these refined sugars have no FAN so the total amount of FAN is even lower. FAN is an inportant yeast nutrient and reduced levels will lead to sluggish or even stalled fermentations..and an open door to Mr Infection !!
K