Once strained and bottled, colour changing gin keeps for up to a year, stored sealed and out of direct sunlight. The kit it comes from keeps for 18 months from packing, with the best before date printed on the outer box, and it leaves us with at least 12 months still to run on that date. Dried blue pea flowers do not go off in any dramatic way: they fade slowly in colour and aroma, which is the one reason to keep them in the dark.
So there are two clocks here, the kit and the bottle, and sunlight is the enemy of both.
Do dried blue pea flowers lose their colour?
Gradually, yes, and light is what does it. The blue in butterfly pea flowers is a natural pigment, and natural pigments fade when they are left in the sun, just as a curtain or a print does. Kept in a dark cupboard, sealed and dry, the flowers hold their depth of colour for a long time.
The colour change itself is chemistry rather than freshness. The pigment shifts with pH: blue in the neutral spirit, turning pink or purple the moment something acidic goes in. That reaction does not weaken with age. An older flower gives a slightly paler blue to start with, so the finished gin starts a shade lighter, but it still changes colour exactly as it should.
The Colour Changing Gin Kit also includes an Earl Grey botanical infusion, which is a tea-based flavour element rather than a colour one, and that fades the way any tea does: softer aroma, flatter flavour, nothing worse.
What happens to the kit after the best before date?
Quality declines rather than the kit becoming unsafe. This is a flavour-led kit, like our other gin kits, the rum kit and the chilli kit, so the ingredients taste and look a little less punchy with age.
That is a completely different sort of ageing from the two kits in our range built around active ingredients. The wine yeast in the hedgerow wine kit and the rennet in the cheese kits may stop working reliably after their dates, and a batch fails outright. Blue pea flowers have no job that they can fail at: they sit in the spirit for about 12 hours and release their colour.
If an older kit gives a paler blue than you hoped, leave the infusion a little longer and check it with the pipette before straining. Depth of blue is largely a function of contact time.
How should you store the kit between batches?
The kit makes up to five 700ml bottles, so most people work through it over months rather than in a single session. Reseal the flowers tightly, or put them in a grip-seal bag or small airtight tub, and keep them somewhere cool, dry and genuinely dark.
Dark matters more here than for any other kit we make. A clear jar of blue pea flowers on a sunny shelf looks beautiful and will be noticeably paler by the summer. A cupboard, a drawer or the box they came in are all better homes. Keep them away from the hob and kettle too, since steam is bad for any dried botanical.
Buy the gin when you are ready rather than up front. You add a bottle of plain, uncoloured gin per batch: a coloured gin masks the effect, and heavily flavoured gins are often more acidic, which can set the change off early.
How long does the finished gin keep?
Up to a year once strained and bottled. Keep it sealed and out of direct sunlight, and it will still perform its trick at the end of that year just as it did on the first night.
Storage really is about light rather than temperature. A bottle of blue gin standing on a windowsill will lose its blue over weeks, not months, because the same pigment that makes the drink work is the one that sunlight bleaches. A cupboard keeps it vivid. If you want to show it off, bring it out for the pour and put it away afterwards, since the magic is in the pour anyway: the change happens almost instantly when the mixer goes in, and it stays changed.
Fine sediment or a slight haze from natural botanicals is normal, not a sign of age. Strain it again through the sieve or a filter bag without squeezing, let it settle and decant off the clear gin if it bothers you.
If the colour is not changing at all, the usual culprit is the mixer rather than the gin. The change needs something acidic, and some diet tonics are not acidic enough, so use a proper tonic or add a squeeze of lemon and test with the pipette before you serve.
What about the non-alcoholic version?
The blue pea flower syrup keeps for a month in the fridge, which is a much shorter life than the gin because it is sugar and water rather than spirit. Warm 350ml of water with 350g of sugar until dissolved and steaming, turn off the heat, add 10 blue pea flowers, steep for 30 minutes, then strain and bottle it.
Poured over ice and topped with lemonade, it turns from blue to pink up the glass in exactly the same way. It is the version to make if you want the colour changing gin kit to entertain a table where not everyone is drinking. The gin itself is for adults aged 18 and over.
Colour changing gin FAQs
How long does colour changing gin keep once made?
Up to a year, once strained and bottled. Store it sealed and out of direct sunlight, and label the bottle with the date you made it.
Do blue pea flowers go off?
Not in the sense of spoiling. They fade slowly in colour and aroma, and sunlight speeds that up, so keep them sealed in a dark, dry cupboard.
How long does the kit last unopened?
Eighteen months from packing, with the best before date printed on the outer box. Kits leave us with at least 12 months still to run on that date.
Why has my blue gin lost its colour?
Almost always light. The natural pigment bleaches in sunlight, so a bottle kept on a sunny shelf pales over weeks. Keep it in a cupboard instead.
How long does blue pea flower syrup keep?
About a month in the fridge. It is sugar and water rather than spirit, so it has a much shorter life than the gin.
Fancy a bottle that changes colour in the glass? Take a look at our gin making kits.
