Transporting wine/olive oil back to states

I don't think there is any protocol. They are not putting multi bottles in carry on unless they buy at a duty free shop behind security with a direct flight home. You can put it in checked luggage and make sure it is very well padded. There is a limit on wine but not on olive oil.

Not in your carry-on, in your checked luggage, since you can't bring anything more than 3 oz through security.
If you bring olive oil back, make sure it is in a can or VERY sturdy bottle. Wine bottles make it fine but olive oil in thin bottles, not so well, as I have learned.

I’ve done both, often and a lot of it. In our checked bags. We used the bubble wrap wine bottle carriers you can get from Amazon. For olive oil, we wrap in clothes, like my husband’s socks, and put in plastic bags. I keep the receipts for the wine with the bottle. I don’t buy expensive wine in Europe for several reasons. I can’t think of a time I’ve spent more than 20 euro/bottle, usually much less. I believe a a person is allowed 1 liter of alcohol, which would be 1.5 bottles, however when I’m asked what I have I generally say, “a couple souvenir books, towels, some wine, olive oil” etc. They never ask how much. If they did, I would tell them, and I believe the tax is 5%, which wouldn’t break the bank.

We just brought home 7 bottles of wine and 1 bottle of olive oil from Portugal. We don’t shop and typically the souvenirs I bring home are consumables, towels, sometimes little trinkets for the Xmas tree.

Google "wine sleeves" and you will see some bottle protectors. I use "Jetbag" which is leak proof but provides less padding. I always ensure that all jetbags are surrounded by plenty of clothing.

You can bring some wine and olive oil in your carry on bag even if over 100 ml. However...

1) It must be bought at duty free within the past 24 hours;

2) It must be in a sealed, security bag;

3) the receipt must be visible

If you connect to another flight, they then have to go into checked luggage.

You are allowed to bring back one liter of alcohol duty free. While you can bring back as much as you want, you may have to pay duty on more than one liter. Keep your receipts as duty is usually 3% of the cost of the alcohol.

In general, you can bring back up to $800 in goods duty free. Over that and it's 3%.

I say "may" have to pay because quite often, for a small amount, the officers may not want to deal with the paperwork involved.

Always declare your alcohol or you will definitely pay the duty and possibly be fined.

We flew back from Rome via Dublin (aerlingus) in March. We had purchased a couple of bottles of wine and olive oil at grocery stores in Rome, those went in checked bags, I do lots of wrapping with clothes/plastic bags - I also asked to take a box from the grocery store and cut it down to size to add more protection. I had a few pieces of bubble wrap from things I brought to Italy and used it all - but didn't buy extra wrapping.
We knew we wanted to buy a few bottles at duty free in Rome, but I was worried because of Dublin connection. I asked at the ticket desk in Rome and was assured that we wouldn't be transiting outside of security in Dublin, when we got our connection. So, I bought the bottles at duty free, the clerk put mesh sleeves on each bottle before sealing them all in the labelled duty free bag. When we got to Dublin, we actually did have to go through another security check, but I just put the sealed bag on the conveyor belt and there was no questions. I think that was a special transit security line, not the normal one that you would go through entering an airport. So, if you happen to be transiting through Dublin, don't panic just keep the duty free bag sealed.

Bottles are pretty tough, but the danger is from hitting a sharp point, like the edge of a stair, a protruding rail or handle or the top of a can. Putting a piece of cardboard as mentioned in the bottom and sides of a soft duffle bag is a good idea.

I remember once in the '90s, when a fellow traveler brought a whole case of wine on board as his carry-on.

We have been successful many times with wine in checked luggage except for one time -- what a mess. I wore pink underwear for a couple of years. For years we used a six bottle, styrofoam, case as carry-on and then we had 9/11.

Bring a large zip lock bag if you plan to buy olive oil or wine. We usually bring back at least one tin of oil each trip. it's in the zip lock bag, then wrapped with dirty clothes centered in our checked bag. We've put wine bottles in our tandem bike cases, but lost one bottle when my hubby wouldn't listen to me and didn't add additional wrapping around the two bottles, they were separated by a piece of cardboard, in a cardboard box, and one broke... how do you like your wine scented clothing and tandem bike?

As everyone else has stated, you can't bring back purchases in your carry on unless you purchase in duty free at the airport. That said, i would rather buy from a local farm than in the airport. I can get that type oil at World Market.