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Flavor Masking

How to stop a product tasting of something you don't want it to.

By Theo Vance, Flavorist5 min read

What is flavor masking and how does it work?

There are four ways to mask a bad taste: cover it with a flavor you want, block it at the taste receptor, bury it under sweetness and body, or coat the ingredient so it never touches your tongue. Most people only know the first one.

Nearly every product that reaches a flavor company has the same problem. Something in it tastes bad, and nobody wants to remove the thing causing it — because it is usually the ingredient the whole product is built around.

That is what masking is for.

First, work out what you are tasting

This sounds obvious. It is skipped constantly, and it is the single most common reason a masking project goes nowhere.

Taste the base on its own — no flavor, no sweetener — and describe it properly:

  • Bitter — the taste you get from black coffee or tonic water.
  • Metallic — like sucking a coin. Usually iron, zinc, or something that has oxidized.
  • Drying or puckering — the mouth-feel of strong tea. This is called astringency, and it is a physical sensation, not a taste.
  • Green, earthy or beany — common with plant proteins.
  • Salty — usually the minerals in an electrolyte blend.

Getting this wrong wastes months. A metallic taste will not respond to a bitterness blocker, and no amount of extra fruit flavor will fix astringency.

The four ways to mask

Most people think masking means "add a stronger flavor on top". That is one option out of four, and often the weakest.

ApproachWhat it doesWhen you use it
Cover itAdds a strong flavor the brain notices insteadChocolate over whey protein
Block itStops the bad taste registering at allBitterness from caffeine or stevia
Distract from itAdds sweetness or body so the bad taste is less obviousAnything low-sugar or thin
Keep it off the tongueCoats the ingredient so you never taste itMinerals, some vitamins

Real products almost always use two or three of these together.

Astringency is not bitterness

Worth its own section, because mixing these up is expensive.

Bitterness is a taste. Astringency is a feeling — your mouth going dry and rough, the way it does with strong tea or red wine. It happens when certain compounds grab onto the proteins in your saliva.

Because it is physical rather than a taste, you fix it physically:

  • Thicken the product slightly, so the mouth stays coated
  • Add a little fat, if the product allows it
  • Raise the pH a little, if the product allows it

Adding a stronger fruit flavor to an astringent drink just gives you an astringent drink that tastes of fruit.

Water will lie to you

If you test a masking system in plain water, you will get a result that has almost nothing to do with your finished product.

In the real thing:

  • Protein grabs onto flavor molecules and holds them back
  • Fat dissolves flavor and slows how fast you taste it
  • Gums and thickeners change how strong everything seems
  • Acid changes both the flavor and the bad taste underneath it

So test in your actual base, at the actual dose, at the temperature people will drink or eat it. And if the dose of your active ingredient is not final yet, test at the highest level you might use — masking does not scale up neatly, and a system tuned for 20 g of protein will not hold at 30 g.

What masking cannot do

Three honest limits, so you do not spend six months finding them out:

It cannot rescue a dose that is too high. Past a certain point the answer is a lower dose, a different form of the ingredient, or a different format — a capsule instead of a drink.

It cannot survive a process it was not built for. A system designed for a cold drink will not necessarily survive being heated.

It cannot get you to zero. Good masking makes a product genuinely pleasant to drink. It does not make the ingredient disappear. If your brief requires nobody to detect anything at all, you probably need to change the formula rather than the flavor.

What to send a flavor company

If you give them all of this up front, you get useful samples in the first round instead of a list of questions two weeks later:

  • The full recipe, including gums, acids and colors
  • The active ingredient, which exact form of it, and how much
  • The full process — temperatures, how long, how it is filled and packed
  • The packaging and how long it needs to last
  • Any label rules: natural only, organic, non-GMO, allergen limits
  • What you can afford to spend, per unit of finished product
  • Who decides whether it tastes good enough, and what "good enough" means

Coverage

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FlavorsChocolateVanilla
ApplicationsSupplementsBeveragesProtein Powder
FormulationFlavor MaskingTaste MaskingBitterness MaskingOff-Note Masking