This post is rather late as the lunar Chinese New Year (CNY) is just 5 days away. I have been busy with my orders and couldn't find time for this write up. Stealing some time now to get this done. I hope this post can be of some help this year or the next CNY.
For those who want to cook pineapple jam instead of using store bought jam, here are the tips I have gathered from my own experience. Below is a list of pros and cons of cooking your own jam.
Pros :1. No preservatives and stabilisers
2. No flour added to thicken the jam
3. You control the sweetness of the jam
4. You control the consistency of the jam
5. You control what spices you want to use and how much you want to use
Cons :1. Prepare to stand at stove for at least 2 hours
2. You sweat buckets
3. Risk getting scalded
4. You don't know when to stop cooking the jam
5. Risk burning the jam
6. You need to hand-grate the pineapples
I have never used store bought jam but the feedbacks I got from friends who do, weren't that great. Either the jam is not fragrant enough, no bite, too hard and dry or too sweet. Based on these feedbacks, I will explain why I did my pineapple jam my way.
There are many pineapple jam recipes online, so I won't elaborate here. The basic recipe is of course, pineapples, sugar and spices, if you like. You shouldn't add flour to thicken your jam at all. Taste is subjective to each individual so do not follow the recipe blindly.
Things you need to cook pineapple jam1) Stainless steel or glass bowl (to collect grated pineapples)
2) Stainless steel or glassware for cooking
3) A wooden spoon (I dedicate 1 wooden spoon solely for cooking pineapple jam
4) A grater
5) A pair of gloves (to protect your hands from the acidity)
6) A corer or back of spoon to 'blind' the pineapples (I dig out those 'eyes' instead of cutting)
7) A lot of patience
8) Water to hydrate yourself
9) Some upbeat music for this monotonous work (at times, I sing along with Enka too)
*Picture Added

FragranceMany recipes likes to use unripe or half-ripe pineapples. My personal concoction uses half-ripe and ripe pineapples. Half-ripe pineapples will provide the 'bite' while ripe pineapples will provide the fragrance. Just like cookies and cakes will emit the aroma to tell you they are done, ripe fruits give out fragrance to tell you they are ripe and ready to be eaten. If you cook unripe, half-ripe and ripe pineapples separately, you'll get what I mean. Also, I do not strain the juice of the grated pineapples. Yes, it will take longer to cook the jam, but the full flavour is retained.
SpicesI used cinnamon and cloves for my jam. Traditional Nyonya pineapple tarts use star anise too. Alhough I might have some minute Nyonya blood somewhere along my ancestral line but I am a Teochew too. And to Teochews, we use star anise for braised duck or pig trotters. So I never gotten use to the idea of adding star anise. If you dislike the smell of these spices, you can just cook the jam with sugar. But at least give the cloves a go; it does go very well with pineapples. I will use 2 cloves for 1 pineapple.
*Picture added
BiteAs mentioned, half-ripe or unripe pineapples will give you more fibre, thus the 'bite'. Do not blend the pineapples with a food processor, always use a grate to grate it coarsely. During cooking, the grated pineapples will dehydrate and shrink. Do not grate the core of the pineapples in attempt to increase the volume. The core even after being grated, will remain quite coarse and fibrous. Personally, I do not like the texture.
SweetnessCooking fruits can be tricky as they have sugar content. Though pineapples are mostly sour, it does contain sugar. During heating, it will break down to fructose. When the juice evaporates, the fructose will be left behind. Adding sugar is a must to preserve the jam. I usually add 70% of the sugar the recipe stated and taste the jam before slowly adding more sugar if required. I used 65g of sugar to 1 pineapple as a guide. I only add sugar when the pineapples started to dry up. The chemical composition of sugar is made of of Carbon, Hydrogen and Oxygen. When heated, sugar will breakdown in to water and carbon, thus causing the jam to caramelise. The jam should be sticky with a golden hue. It should not be too dark.
Done-nessThe tricky part of cooking the jam is knowing when to stop. If you are making an open-faced tart, you need the jam moist. If you are making closed tarts, the jam cannot be too wet or it will be difficult to handle during wrapping. For me, I am clumsy with closed tarts. I only make open-faced tarts. I cook the jam till it coats the wooden spoon and the jam doesn't fall off the spoon immediately. However, when you flick the spoon, some jam should fall off. I'm sorry if you find this description vague. You need to cook it to experience it. After the jam is being cooled, remove the spices and store the jam in a container. It should be refrigerated till ready to use.
*Update*
In my haste yesterday, I forgot to mention that you should use a pot which is wide. The bigger the area, the faster the evaporation. This will help to cook the jam faster. But don't go greedy and cook too much jam at a time.
Have fun! 頑張ってね~~