Such a fun gift! I have made lots of vinegars, and enjoy them very much. First, don't actually boil the vinegar, but do heat it to just below boiling (full boil can alter the vinegar, which should be avoided, though I would guess that it would take a lot more than a few seconds of boil). Also, you don't really want to 'cook' the herbs, but the heat helps. I usually go until it's steaming, then use it. Reasons--the heat helps pull the oils out of the herb leaf.

Also, some recipes call for leaving the herbs in the vinegar after they've steeped. I would avoid this--most herbs get really yucky looking really quick, and can lead to the vinegar molding as well. A couple of exceptions are garlic, dried chili peppers, and rosemary, which is strong enough to hold up to the acid levels. Other herbs really aren't worth it, and once the vinegar level gets lower than the herb, that's when you can get mold issues.

Other tips--keep an eye on them, trying them every few days until they get to the level you want. Some herbs don't take nearly as long, and oversteeped can cause bitterness--I generally do 2 weeks at a max. (did a garlic chive blossom that really only needed 4-5 days). It's the more tender leaf ones that don't take as long. If you start noticing any difference in flavor, but would like them stronger, strain that batch of herb out and add more for a second infusion. Try some different vinegars if you'd like--I love the garlic chives in a seasoned rice vinegar for stir frys. Red wine vin with rosemary and garlic is also nice, especially for veggies. Champagne vin is a little spendier, but nice with tender herbs like lemon thyme or basil.

Thanks so much baloonflower for your insightful input! You've given me food for thought! I'm also making some herbal bath tea bags for some of the women on my gift list...... I'm new to both of these projects, soooo, keep your fingers crossed! ;)

cugal - welcome to the Herb Forum. However, most of the preserving and canning experts are over on Harvest. They are particularly knowledgeable on safety issues. I'm sure they'll be able to help.

Here is a link that might be useful: Harvest Forum

I don't think there should be any problems with infusing some herbs in straight vinegar. The pH of vinegar(5% acidity) is about 2.4 and no bacteria or harmful microbe can survive and produce toxin. Though, you might want to check with the CANNING experts.

Seysonn--

You don't have to can infused vinegars, though for best life they should be stored in the fridge. I only do that with some of the favorites, and the rest are in a cupboard.

The reason you don't use straight distilled vinegar for herbal infusions is that it's just too harsh, and you won't get the lovely flavor to come through.