Most people will say you still want them to have some moisture in them when you go to put them in the jars. If the stems are snapping, they are VERY dry. Stems are more likely to just bend if they have any moisture since the stems are so strong. They also say that slowly removing the moisture by drying the outside of bud, then putting it in the jar to let the moisture re-distribute throughout the bud, then drying it again. This must be done with care though! Don't try this method unless you are willing to check your buds regularly to make sure they aren't drying out too much or staying in jars too long. If you over dry them once, the original moisture is gone for good. On the other hand, if you leave them in the jars too long, you will get mold on the buds and you'll ruin the whole jar (really sucks, happened to me once with some solid bud).
So, after that horrible accident, I tend to dry my buds out all the way before putting them in the jar so I can keep them in the jars long-term until I smoke them. This works for me because I only grow for personal use, so I have a lot of bud all at once from a grow, then slowly use it down. Obviously, I don't want the bud to be completely dry when I go to smoke it (too harsh) so I take a smaller jar (a week or two's worth of bud) then do one of two things to make it re-gain some moisture. My preferred way is to take a small peice (like a couple square inches) of orange peel and putt it in the jar with the bud overnight. By the next day, the bud has a nice amount of moisture (not too much or too little) and might have a faint hint of orange (very subtle if at any). The other way, if I don't have any oranges or suitable fruit (I've also done apple and mango that worked fine) on hand, is to take a piece paper towel and slightly dampen it (not dripping wet, just damp), fold it up to a small square, and put it in the jar with the overly dried bud overnight. I get the same result without any hint of fruit smell.
I recognize that some people believe you lose some of the good flavor of the bud by not drying it out properly (curing it). So, I recommend trying it both ways and deciding what works best for you. I just failed at keeping track of how moist one great jar of weed was and made it mouldy and ruined it, so I'd rather still have great bud that might not have it's peak flavor (still great) without the mold.