I need some salt piles for cooking but I can only find a few.
350 guaranteed samples can be found in 162 different locations. Locations with the greatest numbers are:
- 14 centered 330 ft S of Merryfair Farm (map)
- 13 in Riften (The Rift)
- 9 in The Midden (Winterhold)
- 9 in Mistveil Keep Barracks (Riften)
- 8 in Fellglow Keep (Whiterun Hold)
- 6 in The Bee and Barb (Riften)
- 6 in Riften Warehouse (Riften)
- 6 in Haelga's Bunkhouse (Riften)
- 6 in Temple of Mara (Riften)
Information sourced from UESP.
You can also usually purchase it from a lot of merchants especially inkeepers and other food merchants. They are very commonly found in barrels and sacks too.
Salt piles are a common random food-loot item in barrels and sacks in areas where mages are common. In such areas, you'll find salt piles and other alchemical ingredients that are apparently considered by Skyrim inhabitants to be food-like (such as garlic, frost mirriam, and elves ears) more frequently than the ususal potatoes and cabbages food-loot.
Consequently, the best place to find respawning salt piles is warlock lairs. Due to the way location respawning works, you can maximize salt acquisition by not clearing the dungeon. (If you kill the leader of a lair the location is marked as "cleared", which means that it will still respawn but take much longer to do so.)