Not much — and that's one of the reasons blue spirulina works so well as a natural colour. Unlike ordinary green spirulina, blue spirulina is made from the extracted blue pigment, phycocyanin, rather than the whole spirulina biomass. At the small amounts normally used for colouring, its flavour is generally subtle enough to disappear into the rest of a recipe. Your blue vanilla latte should still taste like vanilla. Your coconut lemonade should still taste like coconut and lemon.
Does blue spirulina taste fishy?
It shouldn't.
Good blue spirulina doesn't have the strong seaweed-like character people sometimes associate with green spirulina.
If you taste the powder directly, you'll know there's an ingredient there. And if you put a lot of it into plain water, you'll probably notice it. But neither of those is how most people actually use blue spirulina.
In a finished drink or dessert at a normal colour dose, the other ingredients usually do most of the talking.
Some recipes hide it better than others
Blue spirulina is particularly easy to work with in recipes that already have a clear flavour of their own.
Vanilla, coconut, mango, pineapple, mint, white chocolate and similar flavours all give you plenty to work with. Milk and oat-based drinks are forgiving too.
Something extremely delicate — lightly sweetened water, for example — leaves the ingredient with nowhere to hide. You may notice the powder sooner there than you would in a milkshake or gelato.
That doesn't necessarily mean you need another flavour. You may simply need less blue spirulina.
More blue isn't always better
It's tempting to keep adding powder because the colour gets deeper.
Eventually, though, you're using more ingredient without necessarily making the product any more attractive. You're also making its own flavour easier to notice.
For most recipes, you're looking for the point where the colour is unmistakably blue without changing what the product is supposed to taste like.
Once you're there, stop.
What flavours go well with blue spirulina?
You don't actually need to choose flavours for blue spirulina. Because its flavour contribution is relatively small, you have quite a lot of freedom.
But if you're looking for ideas, these are easy places to start:
Coconut for lemonades, smoothies, cocktails and frozen desserts.
Vanilla for lattes, milkshakes, frosting and ice cream.
Mango or pineapple when you want something more tropical.
Mint for drinks, chocolate and desserts.
White chocolate for ganache, frosting and bakery applications.
Milk or oat milk for simple café drinks where the colour itself is the attraction.
There's no reason to stop there. If the flavour works without blue spirulina, there's a good chance you can make it work with it too.
Will my customers taste it?
At a sensible dose in a flavoured recipe, blue spirulina should be the thing they see, not the thing they taste.
That's the easiest way to think about it.
Use enough to get the colour you want, taste the finished recipe, and don't keep adding powder simply because you can make the blue darker.
FAQ
Will blue spirulina change the flavour?
At normal colour doses in a flavoured recipe, it should stay subtle. Use enough for the colour you want, taste the finished recipe, and stop before the ingredient becomes noticeable.