The Color-Changing Martini

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Picture of The Color-Changing Martini
This drink smokes elegantly, changes from a calm blue to fuschia as it cools from room temperature to drinkably cold, and tastes like a dirty martini.

(For the non-alcoholic, dry ice-free version, see the color-changing sports drink)
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Step 2: Red #$@%! Cabbage?

Yes. Red cabbage contains a water-soluble anthocyanin that is a pH indicator. At low pH (acid), it's red. It's purple at neutral pH, and goes blue then green as the solution becomes alkaline. You're not going to see the full range here, because we want the drink to be, well, drinkable.

To get the indicator, chop up a cabbage leaf, put it in a bowl with some water, and microwave until it's boiling (or just add boiling water and allow to steep). A purple pigment will stain the water.

Step 4: Present

Give the recipient the drink. Tell them to watch closely, then add a chunk of dry ice. It will sink to the bottom of the drink, and bubble away happily, slowly cooling the drink. It will also neutralise the baking soda and change the colour of the martini. See it in action in the video below:

(that's not me saying "wow, that's wicked" by the way. This drink was mostly made as a way of keeping three small children entertained while their mother was out Christmas shopping. They liked the look of the cocktail, but thought the mocktail version was "really disgusting". I did warn them that it was just salty, cabbage-flavoured water...)

It should go without saying, but wait for the dry ice to disappear before trying to drink the cocktail. You do NOT want to swallow any dry ice!
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attaboyix1 year ago
Why not beets? I would have thought that to be the obvious choice?
makendo (author)  attaboyix1 year ago
It's all to do with the pH at which the color changes. So beets have a great color... but they don't change unless you take the pH *very* high (12-13, and they go yellow). So this would create something undrinkable. It turns out blueberry juice isn't that great either - the change in that case happens at too acidic a pH. Cabbage juice anthocyananins turn out to be just right.
Have you tried blueberry instead of red cabbage? Should be essentially the same indicator, more pleasant taste from what else gets extracted.
makendo (author)  jaegerschlager4 years ago
No, I haven't. Good idea though, as blueberries also contain anthocyanins. I was mostly looking for something that went with the salt. Any suggestions for a slightly salty, blueberry-flavoured cocktail welcome!
wb7ptr makendo1 year ago
Someone in one of the bars here in New Orleans is going to see this and steal your idea. That is if they haven't dreamed up their own version. That drink would be a hit here, especially during Mardis Gras.
tinker2342 years ago
nice idea i wonder if i could make a virgn verison
The article has a reference to a "smoking sport drink" for those who don't drink alcohol. It's in the text above describing this version.
RDeUslar2 years ago
Hi, one of my students chose your instructable for their advertising workshop, they did the nameing, packaging and ad campaign, hope you like it.
That has nothing to do with this Instructable as far as I can tell.
makendo (author)  RDeUslar2 years ago
Good stuff - hard to make a drink made from cabbage juice appear sexy, but I think they managed it!
wb7ptr1 year ago
I had heard liquid nitrogen also. Dry ice is frozen carbon dioxide. The liquid nitrogen thing is some new fad going around. Hopefully it will end soon because it's causing a lot of harm.
ccrazed2 years ago
Not a great idea to use dry ice. A girl in the UK had a drink with dry ice and nearly died, she was lucky but had her stomach removed.
That was liquid nitrogen according to the news, she took the down in one challenge. I guess if the dry ice were to be placed under a gauze which was fixed to the glass it would be a whole lot more reassuring.
makendo (author)  ccrazed2 years ago
Yes, I would recommend those of a nervous disposition to stay well away from this drink, or to just make the drink change colour by adding a clear acidic drink (there are lots - Sprite works). I think it's fair to say in general that if you don't know anything about an ingredient, you should treat it with extreme caution (I think a guy recently died from eating live cockroaches in a competition). If you make a drink with boiling water and consume it before it cools, you will scald yourself extremely badly. So if we give someone a very hot drink, we warn them of that fact. Same principle applies here. Ingesting dry ice is dangerous, so wait for the cocktail to stop smoking before drinking it.
kcabral285 years ago
Just a thought, If you dissolved baking soda into water and then froze it into small ice cubes, would you be able to create alkaline ice and scrape off the sodium?  Isnt there a way to desalinate water by freezing it? Even if you can't remove the sodium from the ice maybe a slow release of base from the ice cubes as they melt would allow the color change to last longer or even swing back to blue after the dry ice completely sublimates? I'm definately trying this out soon.  Great idea!
makendo (author)  kcabral285 years ago
Thanks. Lots of ideas here! Freezing a salty solution generates ice + an even saltier solution, until eventually you'll start crystallizing out the salt (in this case, sodium bicarbonate) and you'll have a mixture of salt crystals and ice when the whole thing solidifies. I'd encourage you to experiment, for sure, but work it out with water first - don't waste all the booze! 
belsey makendo3 years ago
How about using potassium bicarbonate instead of baking soda? They do make it food grade and is used in specialty baking instead of sodium bicarbonate -- it should have a similar effect without the salt...
makendo (author)  belsey3 years ago
I'm sure it would work, but I'm much less sure that the effect of the potassium on taste would be beneficial. "Lite" salt substitutes about half of the Na in NaCl with K, but tastes pretty vile (it has a sort of bitter aftertaste, though YMMV).
ilpug3 years ago
I really really need to do this.
cmanuel13 years ago
Just dropping in to say "Awesome, Dude!" I've featured this on today..

makendo (author)  DotatDabbled4 years ago
Hey, thanks Dot... funny, I never thought of it as creepy or Halloween-worthy... but dammit, you're right.
jgroenert5 years ago
I don't heat the cabbage. I make cabbage indicator for children's science classes by blending cabbage to a pulp with water. Strain and freeze xtra for later use.
Lovely drink . Would pickled cabbage brine work?Would add flavor . I am going to have to ask the local martini miester.
makendo (author)  jgroenert5 years ago
Thanks. Yes, you can see in the photo of the chopped-up cabbage that the colour is leaching out before the cabbage is heated.
Haven't tried pickled cabbage brine - but I think it's salty enough already!
Nyxius makendo4 years ago
 instead of using sodium bicarbonate to balance the solution why not use dilute 3% hydrogen peroxide?  it's not dangerous if consumed in the small quantities you would use in the drink.  Plus there is no salt as a by product... just plain old H2O.

If you try this method instead of baking soda, then I would strongly recommend mixing in the proper amount of peroxide into you indicator well before serving since the reaction is probably going to be pretty slow.
Nyxius Nyxius4 years ago
 Oh and just to give you the chemistry...

NaHCO3 & {H+ & (Ac)-}  --> Na?(Ac) & H2CO3 -->  Na?(Ac) & H2O & CO2

H2O2 & {H+ & (Ac)-} -->  2(-OH) & {H+ & (Ac)-}  -->  2(H2O) & (Ac)-  

(Ac)-   + CO2 -->  (Ac)-  & H2CO3  -->  {H+ & (Ac)-} & CO2

Worst case scenario is that you denature your indicator & it stops functioning...
makendo (author)  Nyxius4 years ago

Thanks for the suggestion... but H2O2 is a weak acid, not a base, so I don't see how it can replace the NaHCO3. It's also a strong oxidising agent, so as you say, there is a good chance it will bleach the indicator (which is another type of color change, of course!). I'm puzzled by the chemistry you've provided - is "Ac" the acetate ion (usually written OAc)? If so, the top reaction looks like baking soda + vinegar, but I can't figure out the next 2 at all.

Nyxius makendo4 years ago
Sorry...(Ac) is my personal notation for a generic anion (in this case...your indicator?).  Hydroxide is a weak acid like you said, but it is also unstable and usually decays into two hydroxide ions as a mid-step to creating stable H2O and O2.  The hydroxide ions function as your base to neutralize the acid by stealing the hydrogen to make H2O.  I was not sure about what other chemicals are in your indicator solution so the third line is just a guess of what happens after you add the dry ice (anions don't like staying anions from my experience).
Nyxius Nyxius4 years ago
This is a very slow reaction... can be sped up using ultra violet radiation.  Also dissolved oxygen will make the drink taste sweeter.
makendo (author)  Nyxius4 years ago

No, you're confusing anions with radicals... and oxygen is tasteless (just as well, or we'd be constantly overwhelmed with the flavor... in fact, I'm beginning to wonder if you're pulling my leg).
In case you're serious, my advice: DON'T make a drink with pharmacy peroxide. You really don't want to be consuming it (and unless you're sure the reaction has gone to completion, you will be). From the MSDS for 3% H2O2:
Ingestion: Large oral doses may cause irritation and blistering to the mouth, throat, and abdomen. May also cause abdominal pain, vomiting, and diarrhea.

pandaboy2924 years ago
thats sweet. now only if i were old enough to drink.
makendo (author)  pandaboy2924 years ago
Thanks - but no problem, you get the same effect for non-alcoholic drinks - and also see
awesome. ill have to try that. but where do u get citric acid?
makendo (author)  pandaboy2924 years ago
Try a health food store or specialty grocery store.
alright. thanks.
lime juice(and i would assume other citrus juices) works, thats what i used.
Can also use ground up vitamin C pills ( ascorbic acid ) to get the same effect.
Jodex4 years ago
The victory came to the right address :-) Althought I didn't vote for anybody :-P =/
makendo (author)  Jodex4 years ago
Well, that's a vote of confidence anyway! Thanks.
lobo_pal5 years ago
You should know that you can get poisoning from dry ice easily.
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