Blue spirulina colour behaviour

Blue spirulina is happiest in recipes that aren't particularly acidic. Water, milk and many pale creamy bases are straightforward and tend to produce the familiar bright blue.

Add lemon, lime or another acidic ingredient and things get more interesting. Depending on the recipe and how much acid you're using, that bright blue can shift noticeably and eventually lose the colour you were aiming for.

That doesn't mean acidic drinks are off the table. Blue spirulina works in plenty of cocktails, sodas and fruit drinks. It just means you should test the finished recipe rather than deciding on the colour before the citrus goes in.

If you're developing something where consistency matters, measuring the pH of the version you approve is useful. It gives you another reference point when you make the next batch.

A quick encounter with warmth is one thing. Cooking blue spirulina for an extended period is another.

Phycocyanin is heat-sensitive, and prolonged heating can leave you with a noticeably duller colour. Heat and acidity together are particularly unfriendly to it.

For something like a glaze, syrup, frosting or dessert base, the simplest solution is usually to add your blue spirulina after the hot part of the recipe, once things have cooled enough for you to mix it in properly.

For baked goods, think about where the blue actually needs to be. A blue filling, icing or finishing element may give you a much better result than trying to make the colour survive the oven.

A beautiful blue in water tells you very little about what will happen in a latte.

Pale ingredients generally make life easier. Milk, oat milk, coconut-based drinks, vanilla mixes, white frosting and pale dessert bases all give the blue somewhere to show.

Strongly coloured ingredients compete with it.

Coffee, cocoa and caramel aren't going to politely disappear because you've added blue spirulina. Neither will a dark fruit puree or a heavily coloured syrup. Sometimes the combination produces an interesting colour of its own; sometimes it produces something that looks like pond water.

So test the ingredient in your recipe, not in a glass of water beside it.

Opacity changes how we perceive colour.

A transparent drink can look intensely blue with relatively little powder, while the same amount in a thick milkshake, gelato or soft serve can look much softer.

This is one reason we recommend judging frozen desserts after they're actually frozen or churned. The liquid mix on your bench isn't quite the finished product your customer is going to see.

The same applies to frosting, cream and other opaque bases.

This sounds trivial until you've done it.

A blue drink photographed beside a window can look spectacular. Put the same drink under warm pendant lights in a bar and it may look completely different.

If colour is an important part of the product, look at your final test where you're actually going to sell it: behind the bar, in the café, under the bakery display lights or inside the freezer cabinet.

That's the blue that matters.

Before any of this happens, keep your blue spirulina sealed, cool and dry.

Don't leave an open pack beside an espresso machine or in direct sunlight, and don't put damp spoons into it. Close the pack properly once you've taken what you need.

Nothing complicated. Just treat it like the sensitive natural ingredient it is.

For the brightest, easiest blue, start with a cold, pale recipe that isn't heavily acidic.

If your recipe contains citrus, heat, dark ingredients or a very opaque base, don't assume it won't work. Make a small version and see what happens.

Blue spirulina isn't a colour code you drop into a recipe.

The recipe is part of the colour.