Khải Hoàn is the most likely to give you a real explanation in English, and Phụng Hưng plays a short video. The others are mostly a look at the barrels and a counter.
In Duong Dong, Khải Hoàn is the name most people know and the one I’d send a first-timer to. The original barrel house is at 11 Hùng Vương, and there’s a bigger showroom at 289 TL47 with vats behind it, both open 7am to 7pm. At the TL47 showroom you can usually get a 15 to 20-minute walk-through in good English if you ask, without booking, and the tasting there of 43 and 45 degrees side by side is the clearest demonstration of the difference I’ve had anywhere on the island. Staff are used to packing bottles for flights and will explain the rules.
Thịnh Phát, on Đường 30/4 in town, is a small traditional factory where you can wander among the barrels on your own. It sells 40 and 43 degree sauce in different sizes, it’s cash only, and there’s very little explanation. I like it for exactly that reason: it’s a working barrel house with a counter, not a tour.
Thanh Hà, at 11/18 Nguyễn Huệ, is the one I’d point keen cooks to, and where I buy the 40 I cook with. It’s a family producer down a side street that takes a bit of finding, with almost nothing set up for tourists and very good sauce. It closes on Sundays.
Huỳnh Khoa, on the Duong Dong bypass in Suối Đá, gives a short tour and a free tasting, has a good range of shrimp paste, candies and pepper sauce as well, and packs bottles carefully for luggage. It’s a good choice if you’re buying to fly.
In the south, Phụng Hưng at 471 Nguyễn Văn Cừ in An Thới is where most tours of the south stop. You sit for a short video on how the sauce is made, look at the vats, then taste and shop, and it sells high-grade 45-degree sauce packed for long flights.
Hồng Đức, in Rạch Hàm on the east side, is a large stop set up for groups. Both are fine if your tour takes you there, and I wouldn’t ride out specially for either.
Higher isn’t always better for every use. A 45-degree sauce is wonderful as a dip with lime and chilli, the way it comes with gỏi cá trích here, and a bit much splashed into a pot. For everyday cooking, 40 is the one I use most. For dipping, 43 or 45.
If you’re doing a day in the north instead, the ฟาร์มพริกไทยแถว Gành Dầu make a better stop than any of the factories, and Khải Hoàn is easy to add on the way back into town.
Can I bring Phu Quoc fish sauce on a plane? Only in checked luggage, in sealed plastic bottles inside a taped styrofoam box, and within your airline’s limit, usually 3 to 4 litres. ห้ามใส่กระเป๋าถือขึ้นเครื่องเด็ดขาด