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Wednesday, January 15, 2020

Coloring beer blue with dried butterfly pea flower (Clitoria ternatea)





Testing how well butterfly pea flowers would color a batch blue, sharing some findings.
   While searching on web for similar attempts, read somewhere that PH is a critical issue, so went ahead with some testings.
   I did an infusion of dried flowers in cold water and it did extract the color quite well.
   To start, did a quick test by adding one drop of phosphoric acid in about a cup of water previously tinted with the blue solution and it immediately went  from blue to purple, like magic 😐
    Took my PH meter, water and lactic acid to setup couple samples at different PH, specifically at 2.95, 3.75, 4.40, 5.07, 5.32 and 6.63. Then added 20 drops of tinted solution to each sample.

Samples ready for testing:



Test results:

Closer look:






Clearly, only after PH 6 (Neutral to alkaline), color still remained blue. PH lower than 6 (acidic), color changes to purple, at different levels.

Then tested a sample with real home brewed beer, a very light SRM beer, on which I measured PH of 4.01.


Guess what happens when added the blue drops?


Yes, looks purple and weird.

Here's a another view;


Conclusion is, unless one produces a neutral to alkaline PH beer, color will not be blue.
That seems to be hard to achieve given the PH drop caused by carbonation (carbonic acid).




9 comments:

  1. Hi, Great post! I have a question. It appears that your SRM beer at PH of 4.01 has yellow-ish particulate matter/haze in it to begin with, and I would suspect that this enhances or changes the violet color at around PH 4. Do you have an idea of what kind of effect a darker beer/base color would have on the final coloration using your method outlined here?

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    Replies
    1. Hi J.W, I have not tested darker beers but my guess is that it will completely off color the supposedly blue effect of the flower. Perhaps a light colored and hazy beer could make use of this process though.

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  2. How much pea flower do you think one would need to colour an entire 20l batch purple? And when would you add it?

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    Replies
    1. Couple ounces I guess, try and error process. Perhaps start with 3oz, add to boiling water for few minutes, strain away flowers, chill liquid and pour in your final beer (in keg or bottles).

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  3. really interesting, thanks! following on from the comment on volume for colouring. you say you added 20 drops (~1ml). what volume of beer was that added to? (e.g. approx 100ml). Also, was there a noticeable flavour? thanks!

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    Replies
    1. Estimated beer sample volume of 20ml, or approximately 20g

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  4. Can you add it to a light beer and then add orange juice to get it to change colour more?

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    ReplyDelete