I've made Thai Penang Curry probably ONE THOUSAND TIMES. Not quite weekly for 25 years. No joke.
Over the last year or so, I've noticed it's surprisingly watery, however I haven't changed my method or my brands of ingredients so what could it be? Has the world standard for coconut milk simply changed, I wonder? (Something similar happened in the US when wheat varieties were changed practically nationwide over a few years; I hear they planned the switchover to be gradual so as not to surprise people.)
I've always used Mae Ploy Panang Curry Paste, usually in envelopes but sometimes in the big plastic tub when I had a bigger refrigerator.
I've always used Chaokoh or Aroy-D coconut milk. Sometimes I've used western brands and never noticed a difference up or down. One time by mistake I used LITE coconut milk and it sucked big-time. The difference I'm seeing now isn't that difference. (Aside: in Hong Kong, they don't allow the product term "lite" and when an importer brings in products labelled for other countries, which is quite common, they paint over the "lite" part of the label. That's good as it doesn't fool people into thinking it's low-calorie, but it's bad that the taste is utterly different.
My method varies a little bit but doesn't affect the results. I always use chicken breast, same day I bought it if possible, sliced and fried in vegetable oil or sometimes the cream from the can. It doesn't seem to matter which. I used to always add a thin-sliced garlic and 5 or so Thai chilis and fry until fragrant before adding chicken, but now that I have kids I don't bother. I've NEVER fried the paste as is often recommended; I just pour in a can of coconut milk and put in the envelope of roux and squash the lumps out for a few minutes. Oh: also julienne 10 lime leaves as finely as possible after removing their spine. Also I boil a dozen pea eggplants 10 min in water separately, then add them to the curry.
OK so for the last 12-18 months, it just seems more watery than I remember. Either my memory is somehow slipping, and it's always been like this, or something has changed (such as the world standard for how much fat coconut milk has). I've actually taken to sprinkling just a tiny bit of flour as a thickener and boiling briefly. Any ideas?
UPDATE: I've now tried Merito brand "Certified Organic" Coconut Milk in Japan. Ingredients include only processed coconut and guar gum (the thickener missing from Chaokoh brand coconut milk, at least now in Japan, not sure about the past or in other countries). I added a whole small can of coconut cream (I forget brand and size) but no joy. Still seemed watery. And I've verified there's no water in the pan from the chicken that would be watering it down. I'll try a different brand of cream next time and report volume and brand.