Cider vinegar is started from apples.
Wine vinegar is made from grapes.
Malt vinegar is started from barley.
White vinegar is made from grain.
You can also use peaches or pears.
I take a good pile of fruit peelings or leftovers and them put in a stainless steel, glass, plastic or wooden container and add as much water as I want to make vinegar. We get enough in one meal to make ours, but you may want to save some in the fridge. You can also continue to add peelings during the first stage.
You can add some yeast at this first stage to get things going faster. This is not necessary since there are microbes in the air.
Making cider vinegar is a two step process. The first is fermentation or making alcohol which is what the peelings, yeast and water are doing. During this stage, it will bubble. When it stops bubbling, it is ready for the second step of turning the alcohol into vinegar.
At this point, you can add vinegar starter, which can be found online and will speed things up or you can use starter saved from another batch. You can also wait to see if the pot "catches" it from the air which is how I did it the first time.
It can take weeks or months for the alcohol to turn into vinegar. You'll know by the smell. Generally, the warmer it is, the faster it will turn to vinegar.
The starter is the grayish white jelly like stuff that forms on the top and settles on the bottom. You can save it in a glass jar with vinegar.
Strain off the fruit peelings with a clean cloth. I use several layers of undyed cotton muslin. I throw the fruit peelings to the goats.
You can pasteurize your vinegar to keep it from clouding. I just store mine in plastic containers to use as needed since we are not using it for food or health reasons.
Making vinegar is very easy and hard to mess up. It will prove to be a wonderful homeschool study and Science experiment. There is much more to the vinegar process than I have shared here, so do an internet search for more detailed information.
I love educational experiments that produce something useful for the household!!