So glad I found this thread! I've been looking for an alternative pectin that I can buy in bulk and is low sugar. Looks like I might be stocking up on some fruit from the farmer's market this weekend 
I have always wondered why over the years, that by a heritage house kitchen door (house over 80-100 years old) why there was always a quince tree/bush. I have seen them since I was little and no one knew what they were for. But last year I found out after I researched what the possible reason was for the farmhouse here which has two of them. PECTIN! When the last missus of the house moved here, the woman who planted most of the herbs, fruits and trees here, it was in the 1920's, right before the Great Depression. There was no running water here until the 1970's and it would have been a 1 1/2-day trip one way to the next town through the rough narrow roads (and still are), the mountains and back. The lady of the house was a reknown canner and she had a lovely huge walk in pantry room (which I documented the beejeebies out of before the old house was torn down).
The plus on making your own is that it can be organic. Pomona is probably made from conventional peels of lemon, lime and oranges.
Homemade Quince Pectin1. For every pound of washed and sliced quince (leave the peels on), add 2 cups of water and combine in a large pot. One pound of fruit yields approximately 1/2 a cup of pectin.
2. Cover the pot and bring to a rolling boil then reduce heat and simmer for about 20 minutes. The fruit will be fork tender. Allow to cool.
3. Strain the quince mixture through a jelly bag or cheesecloth, hanging the bag over a bowl overnight (like you would when draining cheese).
4. Boil the strained juice in a pot over high heat until reduced by half. The pectin is usable immediately and will keep for about a week in the refrigerator. To process the hot pectin for canning, pour it into sterile pint jars (boiled for 10 minutes), leaving only a 1/4 inch of headspace, for five minutes in a boiling water canner. Homemade pectin also freezes well.
To determine the strength of the pectin stir two tablespoons of grain alcohol into one teaspoon of homemade pectin. Juices that are high in natural pectin will form a lot of bulky, gelatinous material. Those with average pectin content will form a few pieces of the jelly-like substance. Juices that are low in pectin content will form only small, flaky pieces of sediment. If the pectin test weak, continue to boil it down further. Do NOT incorporate the test batch back into your main batch of pectin. Toss it.
Generally, 2/3 cups liquid pectin will set four cups of most low-pectin fruit or juice. So as an example, if you are making strawberry or blueberry jam use the 2/3:4 cups ratio. Quince is a pretty reliable pectin producer, but the strength of the pectin will still vary from batch to batch.
Cedar - who may be too late to make pectin this year
