Taste Buds and Vaper's Tongue
Can't taste your vapor?


With your favorite flavor loaded in your device, you inhale and taste... Nothing...
For starters, there's no reason to Panic!
Vaper’s tongue is a term used for those times when your taste buds just decide to pack up and go on vacation for a while. It’s not a medical issue. The good news is that it's also not a permanent condition.
New vapers especially experience moments where they seem unable to taste the flavor in the vapor. Some veteran vapers also experience the same thing. A small number of people frequently experience this issue fairly regularly even after vaping for months or years.
There's a few different reasons this phenomenon can happen. Keep in mind this article isn't coming from a medical standpoint, so these concepts are strictly speaking, not scientific.
GIVING UP CIGARETTES

The ability to taste things slowly awakens after a lengthy slumber. These new sensations can overload your sense of taste and strange things start happening. Eventually, all the stimulation becomes a little too much and your brain elects to close up shop for a little while to let your taste regroup.
As you adjust to life as a non-smoker this shut down effect is likely to happen several times. These shutdowns usually last anywhere from a few hours to a couple days. Gradually, your taste buds start firing up again and you'll just realize at some point the flavor has returned all on its own.
DEHYDRATION

The result of this action is a dry mouth. With an amount of the moisture removed from your mouth, a thin film might form on your tongue. The film acts as sort of a barrier isolating your tongue (and taste buds) from the vapor.
When this happens, it's incredibly easy to fix. Water. Simply increase your water intake while you vape. If you find there is quite a bit of film built up on your tongue, you can scrape it off with your toothbrush. It's kind of a weird sensation, and if your family sees you, you might get funny looks, but it's quite effective at removing any buildup in your mouth.
THE SAME OL' SAME OL'
Is there any particular flavor you call your all-day vape? Do you put out more white clouds than the Polar Express?

This cause is another easy fix. Shake things up a little. Experiment with some other flavors. Even if you like to stick to what you know, try to find two or three other flavors to swap between to keep things fresh.
BEING SICK

The sense of smell is very tightly integrated into the sense of taste. When you are unable to smell effectively, it generally also means your sense of taste is equally dulled.
Since there is still no cure for the common cold, your best bet to beat this one is some chicken soup and a comfy blanket.
FOR NO REASON AT ALL
And then there's just the unexplained times when your taste leaves you with no excuse at all. It's like your tongue decided to stay in bed that morning while the rest of your body woke up. Maybe your tongue is still holding a grudge over that whole killing your taste buds with cigarette smoke thing.
These are the times that are probably the most frustrating. Nothing is wrong as far as you can tell, your normal flavors just aren't doing it for you.
Some vapers note that they regain their ability to taste e-liquid after switching to a particularly strong flavor helps revive things. Something with a lot of cinnamon or menthol (or both) does the trick.
SOME IDEAS

Is there a bottle of e-liquid you thought would taste great but turns out you absolutely despise it? You can't taste anything anyway, why not break out the terrible stuff and save your good e-liquid for when you can appreciate it. Maybe your compromised sense of taste will actually make that juice you hate actually taste decent.
For that matter it can even be unflavored e-liquid, your tongue won't know the difference anyway. Keep a small supply handy so you can wait out any stubbornness your tastebuds decide to throw your way.

LET IT STEEP FOR A FEW WEEKS
Most e-liquids you thought had no taste or taste bad will blend fully, deepening and enriching in flavor over time. This will allow for your taste buds to recuperate and return to normal.
TASTE SEEMS OFF
BURNT or PEPPERY Taste: Keep your coils wet and your tank full. Dry coils can give a burnt or peppery taste and lower the lifetime of your device. A peppery taste is also a sign that the juice needs to steep longer, or you are getting a small amount of E-Liquid in your mouth from your device.
PERFUMEY TASTE: Some flavors have a strong scent to them, this is usually eliminated with steeping. If the perfumey taste is still present after steeping. The flavor may need some extra steeping to 'breathe.' Remove the cap and dripper tip, store the E-Liquid in a cool dark place (Away from children and pets) for a couple of days.
With your favorite flavor loaded in your device, you inhale and taste... Nothing...