Not that I am aware of.
The vendors that sell the spices used to use barrels , you may be able to get some info from them on where they purchased them.
I have not seen any to date.
You can find most anything, but it is hit or miss. Network with the vendors and you are more apt to find what you want/need.
I didn't see any there
Please clarify, do you mean barrel like a wine cask? If so they are sometimes available by vendors but not a common product. You would have to contact them directly for availably.
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