Try using whole spices instead of powdered, you can put them in a grain bag, or make a sort of "teabag" to make things easier. Ken Schramm (The Compleat Meadmaker) mentioned a nutmeg metheglin he made on pages 132-133 of his book, but does not list the recipe. He only mentions using "freshly ground" nutmeg. Use the freshest, best quality spices you can get. Schramm also mentions on pg#139 "Cloves must be used sparingly in mead. For some reason, mead seems to provide the perfect medium for the transmission clove's flavour & it's numbing capacity... One or 2 cloves in a 5 gallon batch will have an appreciable effect on flavour, small amounts must be the rule." Some spices can have antiseptic qualities when used in higher concentrations, I know clove oil is used in some brands of toothache drops to numb the pain, it may have other qualities that may be detrimental to the yeast, at least in higher concentrations. You might try keeping a logbook of your recipes, notes & fermentation progress; I find it quite handy to be able to look back in my notes to see what I did with a recipe 2 or 3 years ago. Hope you find some of this info useful. Regards, GF.