Instructables

How do you concentrate citric acid?

I'm making this thing, and I was wondering if concentrating the citric acid (from calamansi (Philippine lemon)) would increase output. My friend suggested boiling it, but is there any other easy way of concentrating it? If not, then let boil....

For the meantime I'll boil it to check if it works. If results come back positive, I'll delete this question. If results come back negative, I'll let this question float around instructables for a while.

(Please do help me in putting this in the right category)

kelseymh4 years ago
Categorizing this is a bit difficult. "Play/offbeat" seemed wrong, since this is a very practical, hands-on project. I've moved it to Food/beverages, since you're really asking about how to make concentrated lemon juice, not about using that lemon juice in any particular project. If you don't like the category, please move it. :-)

As for the actual question, you don't want to boil it; that will do things to the chemical composition that you may not want. Rather, you want to make a reduction. Put the juice into a wide, shallow pot or pan, and simmer it gently (no bubbles, just steam rising up). As you leave it on, the water content will evaporate off, and you should get more and more concentrated acid.

I'm not sure whether that will increase the output or not. The acid is just an electrolyte. The current flow should be determined by the relative electronegativity of the two metals you use as electrodes.

I've done this reduction as you describe it, that's the way.

L
jomer3 years ago
I got the same project too! What is the best metals appropriate to use as electrodes? Does boiling the fruit won't loose some juice? Our project is to produce most volts from the other groups. And the fruit we need to use is Philippine Calamansi. need your help on these...
nutsandbolts_64 (author)  jomer3 years ago
I recommend you try the reduction method described above. I've never really had the chance to try it, but it should work. As far as what effect concentrated citric acid has on the output, I'm not too sure. Just increase the surface area of the electrodes, it should work. Speaking of surface area, I wonder what would happen if you used metal fillings as the electrodes... there's too much on my to-do list to really test it out, but hey!
but what are the best metals to be used in the fruit?
nutsandbolts_64 (author)  jomer3 years ago
Honestly, I don't know... The electrochemical reaction that takes place is something I cannot grasp. Maybe ask a question? Go to the upper right most corner of the Instructables website and click the "submit" button. After a new screen appears, go to the lower left and click on "ask a question". It has a question mark as its icon. Follow the instructions afterwards.
rickharris4 years ago
Why would that be? What magic ingredient do limes and lemons have I wonder.
nutsandbolts_64 (author)  rickharris4 years ago
Higher citric acid concentration than most fruits. That's why I prefer to concentrate these some more (hehehe).
Re-design4 years ago
Which ever way works come back here and post the results. LEAVE the question for those who may search later. If you delete it then you keep the results a secrete.

That's not the scientific method.
Ideally boiling it under a reduced pressure would be a good eway to reduce the volume, and use a lot less energy.
nutsandbolts_64 (author)  steveastrouk4 years ago
Due to the current time on my time zone, I cannot perform the experiment at this time. All suggestions will be considered at an appropriate time.

It is a good idea though; I already have an idea of how to do it.
rickharris4 years ago
Unless you totally bound to fruit juice then why not use a more readily available acid such as vinegar - will it work? Experiment..
nutsandbolts_64 (author)  rickharris4 years ago
If I use vinegar, the voltage I'll get is 0.01 volts. so I need 50 or so cells using vinegar to equal 1 cell which uses citric acid.