Can I fly with white powder in a transparent bag?

It's possible that it might cause some concern given that it's unlabelled and white (that dodgy anthrax scare a few years back has done so much damage to air travel...sigh).

However, most airports in Europe you just stroll through and don't have to get checked, quite often. If asked to declare, I'd be up front about it and mention it, rather than have them find it and cause concern.

As far as scanning goes, they've been scanning powder for years. I can't find an equivalent EU document, but the USA's TSA blog has an entire post about travelling with powder. It's worth a read.

Short version: travelling with powder is common. They have easy ways to test it for explosives. Inspections on powder are few and far between, and there is NO ban on travelling with powder.

Hope that helps!

Hard to tell. I do take a bunch of prescription drugs that I have consolidated into a single small zip lock bag for travel and that really looked fairly suspicious. No problems whatsoever in a 100+ domestic+international flights.

Then again, your bag looks even more suspicious and a lot depends on how you may show up against expectations and profiles. This may be easier to pull off when you are a frequent flyer middle aged fat white guy than if you are a first ticket dark skinned young adult from the middle east or mexico.

Best bet would be to check with the airline first and be really upfront about it in security: Toss the bag into a large bin on it's own and then be prepared to answer the questions you'll get.

I would avoid bringing samples of pure caffeine on aircraft because caffeine is somewhat toxic (1-10 g) and therefore is probably prohibited by flight regulations.

Source: http://well.blogs.nytimes.com/2015/05/18/caffeine-powder-poses-deadly-risks-2/

Always carry:

• Labels
• Prescriptions

Even if its in weird packets.

I traveled quite a bit with herbal medicines that always raise issues:

• Powders
• Unmarked brownish/ olive/ sandy colored Pills in similar small plastic
• Herbal oils

So, I carry:

• labels inside/ stuck on each little plastic sachet or bottle
• Detailed written Prescription from doctors
• Printed & signed detailed affidavit letter from doctor
• Smaller legit looking plastic bottles/ cases/ packets

From Parminders answer:

My advise to you would be to carry your coffee powder in the manufacturer's packaging. Keep it sealed if possible.

Exactly the reason why printed labels and such will help.

Usually this wont cause issues but having all this helps calm down the authorities.

The average European airport security is only marginally more patient than the TSA. That is to say, they are mini-dictators in their little realm. On top of that, they're paranoid, overworked and hated by all. It's not a productive mix.

If they see this —and they will— they will inspect it. Some might buy that it's caffeine. Some wont. Nobody can tell you how many that number will be but flights are expensive so it really only takes one guard having a bad day to ruin yours.

If you get stopped by that guard, do you really expect they'll submit it to a substance test before they decide whether or not to pull you off your flight? No. You'll be arrested on suspicion and held while it is tested.

If you need caffeine regularly, buy some tablets (ie Pro Plus) and leave them in their blister-packs, in their boxes. Take them whole or crush them when you get to the other side. Otherwise just wait until you get to a pharmacy and buy new supplies.

I've carried on a container of white powder in the US and China, nobody has taken note of it. I've also carried multiple pounds of white powder still sealed in properly labeled manufactures packaging.

That being said, I wouldn't bring a bag of powder, period. Put it in something more substantial!