How to Make Caviar in Stardew Valley
Caviar is a brand new item you can make in Stardew Valley. To collect it, you need to acquire a Fish Pond from the Carpenter's shop and have one built on your farm.
Now, you have to use a specific fish to create caviar. When you put any fish into the fishing pond, eventually, they're going to make roe, which, if you put into a preserves jar becomes aged roe. This item is different than straight caviar. However, it's made using the same method.
You need to catch a single sturgeon and add it to your fishing pond back at home. You have the best chance of catching sturgeon during the summer and winter months at the lake right near the base of the mountain, where you enter the mines. You have anywhere from a 16 to 11 percent chance of capturing one, so you may need to spend some time there.
After you have it, the fish needs a few days to create roe properly. Go about your business, and check up on the fish pond every day. Eventually, you'll see an exclamation point above the pond, prompting you to offer the fish something to upgrade it. Provide it the item, and you'll have the chance to add another sturgeon to the pond. Do it, and eventually, you should see a small bundle of roe appear near the base of your you can collect.
The sturgeon roe takes significantly longer than other species of fish roe to spawn, so don't worry if it feels like its taking forever. You may need to upgrade the sturgeon pond twice before one shows up.
Now, you need a preserves jar. Place the roe into it and wait a few days, again, continuing your activities per usual. Roe shows up fairly often at your fish pond, so you may want to have multiple preserve jars on standby to continually add more roe to them while you're waiting.
You can freely eat the caviar or sell it on the market for 500 gold pieces.