The questions I receive most frequently about natural dyeing seems to center on the indigo vat and its maintenance. Since 2011 I have been making and using organic indigo vats, an art and skill that I learned from Michel Garcia.
My current vat began in a 5 gallon vessel over 2 years ago. I enlarged it to fill an 8 gallon vessel, and then last year I enlarged my vat again to fill a 30 gallon container. The increased size was needed because I was dyeing larger pieces of cloth.
The vat was made using henna as a reduction material. I chose to use this material because the slow release of sugars is good for a vat that will be maintained for a long time. I add fructose after each use and additional henna when I need to boost the reduction. Lime (calcium hydroxide) is the alkaline.
The vat is used regularly and I achieve excellent color from the indigo. The large size challenges me to solve problems as I encounter them. It would be tempting to discard a small vat that was not behaving well and begin again, but emptying this vat would require a great amount of effort. As a result I’ve learned a lot about maintaining the indigo vat.
An indigo vat is happiest when it is used on a daily basis. After each dyeing session I “feed” it with a bit of fructose, stir it to bring the un-reduced indigo and reduction materials up from the bottom, check the pH, and let it rest for a few hours before dyeing again.
Occasionally I run into problems that I need to solve. Recently I was away from home for several weeks. Before I left, the vat was dyeing rich, deep blues. The color of the vat was a golden bronze and there was a good healthy “metallic” sheen on the surface and plenty of bubbles.
When I returned home the first thing I did was add lime to the vat. When an indigo vat sits dormant for any amount of time it becomes more acidic and the pH goes down. I can test this with pH papers but a good visual indicator is to sprinkle some lime on top. If the lime is immediately “sucked” down into the vat – you can assume that the vat is in need of the lime. If the lime just sits on the surface, the pH is probably fine.
Next, I stirred the vat and waited for it to settle. The color of the vat looked good, as well as the surface. The vat was a clear gold color and there was a coppery sheen on top. But the first test sample resulted in barely any color at all! That was a surprise, since I thought there was plenty of indigo in the vat. I thought I had also been “feeding” it with plenty of sugar. The vat had been used very heavily before I went away. I thought that possibly the indigo had finally been exhausted.
Before adding more indigo to the vat, I decided to add more sugar – a generous amount. Once added, the vat was stirred and I waited until the next day to do another test strip. It produced a blue, though it was relatively light. I repeated the sugar-stir-rest and dyed again the next day. It was darker. I repeated the sequence again, and finally got back to a shade of blue similar to that which I had before going away.
The lesson here is that before adding indigo to a vat, test it thoroughly for pH and reduction. Although it “appeared” to be healthy, my vat was not reduced and the indigo wasn’t available to dye the fibers.
Natural Dye: Experiments and Results 
Catherine my question is about the fructose vat. Can it continue by adding more indigo or is it better to start new? I suppose it depends on how much sludge is on the bottom. (I inherited a vat from one of your recent classes and it is dyeing nicely still.
I have read the way to add more material is to make a mother solution with all 3 fructose, lime and indigo and then carefully add that to the vat. Do you agree?
Thank you for all the good detailed info.
Maureen, I’m glad to hear that the vat is working nicely for you. Yes, you can certainly add more indigo, along with the correct proportions of the other ingredients. The advantage of making a “mother” vat is that you can easily do it with hot water, which will begin the reduction quickly.
Catherine I have a 10 gal week old henna vat that was performing beautifully. I was keeping it outside in the warm air. overnight we had a cold snap and the vats temp in the morning was less than 60 and no color on an 20 minute test strip. there is also little if any coppery sheen on the surface like there had been. 4 days later the vat is inside and I’m still getting very little to no color. ph is good. Each day I’ve scooped a pan full of solution, heat it to 120 add a little henna to it and return it carefully to the vat. I’ve made no progress. the vats temp indoors is 80 degrees. I started to wonder if it needed calx, so I added some to my heated pan solution, let it sit a couple of hours and did a 20 min test strip. it was no different than the main vats test strip, and the calx is not sucking into the vat as you describe. this was a strong vat with lots of indigo and has only been lightly used. Help!!!
Cindy, Be patient with your vat. Since the vat is a new one, and there is plenty of indigo, you should be able to get it back into reduction. Give it a good stir every day, and a spoon or two of fructose. You should not need more lime at this point. The heat should help a lot. Patience….. stir every day…..
Thank you so much for those encouraging thoughts. I’m so accustomed to hydro vats which I can fix in an hour or two. I also have been slowly feeding it cooked henna powder, and the fructose is new information. I ordered some yesterday after searching in town was fruitless. I very much enjoy the “tending” process. It’s a peaceful beginning of my day in the studio. Your book and blogs have been my major guide, thank you for teaching us all the nuances in indigo. Ps today the vat does have a little gleam of copper on the surface and though the test strip is still pale, yesterdays test strips have kept their color overnight. So there is progress!
Cindy Wilson Cindy-wilson-batik.squarespace.com
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Catherine two tablespoons of fructose worked! the vat is dyeing very dark (darker than originally but it was only 5 days old when it quit). Thank you so much!!! what is the disadvantage of adding too much fructose? My vat is large because of the size of waxed cloth I am inserting, but the actual use is maybe 2 or three dips a day with less than a yard of fabric. I’m trying to get a sense of how often to add fructose and how much. 1 tbp at the end of the day? Your book recommends 3 tbs per 5 gal vat but for my limited use that seems like a lot.
The fructose provides a quicker reduction than the henna. It sounds like you’ve got plenty of henna in the vat in order to keep the vat reduced but it won’t help to give it a spoon of sugar or so after each use. Use your instincts! That is how you will truly learn to master the process.
Hi Catherine, I think ive read every comment in this thread and cant find anyone with the same issues im experiencing with a vat right now!
I mixed a new vat with the 1/2/3 ratio of indigo, calx and fructose in a 4 gallon stainless steel pot. I found a bag of calcium hydroxide on amazon for a great price so I grabbed that and used it for the first time in this vat. I did shake the indigo powder in a container with marbles and then added it with the calx/fructose.
I also use a hot plate so I was maintaining the temperature to probably 40-50 degrees during the reduction period. Normally when i maintain a temp between 30-40 degrees i get good results with dyeing.
Basically the indigo never reduced. I would add fructose and stir then leave it alone for hours, sometimes I would adjust temperature just to see if that would make a difference…trial and error is the name of the game!
At one point the indigo and the water completely separated. I could see the indigo just sitting at the bottom of the pot 😦 A brand new vat, unused! So disapointing. I am not sure what to do! cut my losses and toss it or perhaps add more indigo? I tried adding calx and it didnt need it because it didnt “suck” the powder into the vat. I have also been testing the pH throughout, never getting lower than 11.75 and going up to 12 at times. I see you havnt commented on a post in a couple years now but I hope you will see this!
Thank you so much!
Troubleshooting indigo vats is hard, especially from a distance. There are so many variables.
But I will ask a few questions.
How do you know that the indigo did not reduce? What is the color of the vat? Did you try dyeing with it?
Was your indigo sourced from a reputable supplier? Are you sure that you were using fructose? The more common cane sugar is not a reducing sugar.
The heat you applied initially (and maintained) seems a bit high to me. I always begin my vats with very hot water (40-50°C) but I never apply heat during the reduction period. I am not sure if too much heat can damage the reduction but I’m guessing that it is possible.
I might suggest that you repeat the vat with the same ingredients but on a much smaller scale: a one-liter glass jar. You can actually learn a lot by looking through the glass at the reduction, the color, and it’s plenty big to dye small samples.
Hi Catherine! thank you so much for your reply!
I unfortunately ended up discarding this vat and started fresh yesterday after about a week of troubleshooting.
I could tell that the indigo was not reducing because there was complete separation of the water to the pigment. I dipped a glass in the water to observe the liquid and it was clear with some specs of blue floating around, and could see the blue pigment sitting at the bottom of the vat, as well the pH was over 12 and when i dipped a test strip in the vat, there was no transfer of colour.
I started a new vat yesterday around 6 pm, I mixed the pigment with marbles and hot water in a container and shook for a couple minutes as my goal was to be able to use the vat for dyeing later that night if possible. (wish i had seen your comment sooner to try the smaller scale experiment) this time i did not heat the vat during the reduction, it was between 40 and 50 degrees when it was mixed.
I was checking the pH every hour and checked on the vat this morning and it still hadnt reduced. pH was even higher and the water was a nice deep blue.
I reheated the vat, added a tablespoon of fructose and gave a nice stir because I read that stirring the sludge at the bottom can kick up the indigo that is dormant and might release into the vat and help the reduction along. Again checked the pH and temperature and the pH las lowered slightly so thats a good sign. I am wondering if its the fructose sugar that I am using is what is causing me problems. It is from a bulk store and was described as “instant dissolving berry fruit sugar ” maybe it is too weak? or just not the proper kind?
I would be suspect of something called “instant dissolving berry fruit sugar”. You don’t really know what it is! Always look for more scientific descriptions. Most of us need to order fructose as it is not carried locally in grocery stores etc. That may very well be your culprit. You can also substitute honey but that is likely more expensive.
Yes, i think its the sugar i’m using that is causing the issue. Do you have a brand that you recommend for fructose? I am having a hard time finding any locally, called many bulk and health food stores in my city and none have fructose. Do you think if I just add ALOT of the sugar that I have would that eventually work?
If it’s not the right kind of sugar, it doesn’t matter how much you use. It still won’t reduce. I buy mine online. Sometimes through Amazon or from Nuts.com. that way I know I’m getting FRUCTOSE.
Hello!!! I also have problems with my vat. Ph is over 12 and fructose doesn’t work at all. I have checked all the ingredients but I think they are all ok. The colour is Amber although I never had a flower, just some pale blue bubbles. When I dip my cotton fabric it seems to accept colour but indigo wash out. Wbat could I do? Thank you for all the information.
Hi Monica. I would need lots more information in order to help you troubleshoot. What is the size of you vat? Can you list your ingredients and how much of each? How did you put the vat together? Do you know the sources of each ingredient? How has it been since you made the vat? Are you sure that the textile you are dyeing is cotton? That would be a start. Catharine
Hello Catherine, first all all thank you for answering my question and …you are right, more information was needed. I will try to explain. My vat is 23l (about 6 gallon, isn’t it?) I used 1-2-3 method. First i filled my bucket with warm water, about 3gallon, then added 100gr of indigo hidratated, later 200 gr of calcium hydroxide while stirring and then 300gr fructose. It never had a big flower, just a pale blue one about 5cm wide.
Ph was about 14 and I tried to reduced by adding fructose. Stir, wait ,new ph measuremet. m¡More reducing agent, stir, wait, new measurement. I think I added double (omg) the amount of fructose neccesary and ph is still around 13.
I stopped touching and wait untill next day to test with some fabric. My indigo vat continued without a flower but colour was amber so I dipped some 98% cotton fabric. It was a yelowish colour that turned gradually into blue. I continued the process dipping around 8 times after sumerging in water to wash out the exces of indigo. It never went to a deep blue so I asummed the posibility of having used very hot water when hidratating indigo and a big portion was wasted. I proceeded to rinse the fabric and immerse it in water with vinegar but what was my surprise when I returned and there was hardly any blue left on the fabric.The appearance of the vat has not changed since then, neither has the pH.
I have tried 100% cotton fabrics and the result is the same.
The materials used are reliable. I bought the indigo with which I learned and it is the same that I have used now.
Should I discard this indigo vat?
Thank you and sorry for this huge explanation and for my english.
Mónica.
It sounds like you have done everything right – so why isn’t the vat dyeing correctly? My first thought is the sugar. Are you SURE that you are using fructose – fruit sugar?
Ordinary cane sugar that we use in the kitchen in not a reducing sugar. I cannot purchase fructose locally and always need to order it. Honey will also work but that can get expensive. You can also extract sugar from fruit: cook up some very ripe bananas and strain the sweet water for your vat.
The light blue bubbles often indicate a poor reduction, and additional reduction material is required – such as sugar.
When I have problems with vats I always go back to working small in one liter glass jars. I would suggest that you stir the vat well, so that all is in suspension. Then immediately dip out one liter of the solution. Add some fruit water or honey to that solution. Stir it up, let it settle, and see what happens.
Hey Catherine,
I am trying the method of mixing a “mother” vat first in a glass jar using the same ratio of indigo/calx/fructose because this time I wanted to watch the fermentation process take place. I just mixed it and was wondering if this was a normal reaction, I took photos and thought I’d be able to post a photo here with my comment but doesn’t look like I can. Anyway, the calx became kind of chunky… and isn’t dissolving.. is this what normally happens inside a non see through vat container? Like I can scoop the calx (maybe it formed to the fructose powder too? No idea!) and i can see it on the spoon….
Making a vat in glass reveals all sorts of things, including the sediment at the bottom, the color of the vat, and yes the lime. Sometimes, when the vat is first made, the lime seems to swirl around in great storms. But it doesn’t always happen! That is why it’s important to make the vat the day before. Just stir it well a few times after it’s made. By the next day it should all settle down and look fine.
Hi Catherine, I wondered if you could help trouble shoot my organic banana indigo vat? The pH will not rise above 10. Its a 20 litre vat. Earlier there were indigo particles so I added more banana juice to reduce the indigo further. This worked. Then I added some calx and stirred and heated gently. After an hour the pH reading is still 10. There is a bronzy surface and flower and a 2 min test swatch cellulose comes out pale blue. The recipe was 75g indigo and 75g calx plus 2kg bananas boiled and strained. Thankyou for your help.Michele
Michele, your pH is too low. It should be about 12-13 at the start. The proportions to build a quick reductio vat with fruit is 1 part indigo, 2 parts lime/calx, and 3 parts fruit. When using bananas, I typically use one banana per liter, cooked and strained. Add more lime and you should be OK.
Dear Catharine,
first of thanks a lot for generous sharing of your natural dyeing knowledge through your blog and for your book. It has tremendously help me improve my skills, became kind of natural dyeing bible☺ I have a problem with indigo vat for a quite time now. I am using Michael Garcia 1-2-3 indigo vat method and dyeing cellulose and animal base fibers. Unfortunately, I get almost each time yellow spots on fabric after oxidation. My vats Ph is between 9-11 generally. Do you have any idea or tips where the problem might be? Thanks a lot and stay healty. All the best
Umut
I am assuming that your 1-2-3 vats is reduced with some form of sugar and uses lime (calcium hydroxide). I am guessing (only guessing) that the lime may be the cause of the spotting. The quick reduction vats use a great deal of it and it’s very important to keep the textiles out of the excess lime, etc at the bottom of the vat. This means that you must use a basket, net, or some other way to assure that the textile is exposed only to the leuco dye liquid. If vats are small, there is very little room to do good dyeing. The other thing that can help is proper finishing: a very thorough soaking in cold water when the dyeing is finished (preferably overnight), neutralizing in a mild vinegar/water solution, and then a very thorough cleaning – I boil my cellulose textiles in a small amount of detergent for a about 10 minutes. Hope that helps.
Hello
Thank you for the time in responding the the comments above, very interesting to read.
Hopefully you may be able to assist with a problem I have encountered that I don’t see above.
I have many times made an indigo vat of 5 litres, using 25g indigo, 50g hydrated lime and 75g fructose. This I have made in small vats and scaled up for a larger 25 litre vat. Dyed fabric, made clothes, no difficulties. All good.
Today I wanted to make a vat with darker blue. I understand that you can use double the above quantities in the same amount of water. When I did this, the liquid rapidly thickened and became like blue cream. This seemed to occur after I added the fructose.
My method is to ‘wet’ the indigo with hot water. Mix the lime with water, add this the the indigo. Finally dissolve the fructose in water and add this to the other ingredients, making up to the required amount of water as I do so.
Can you give me any clue as to why it has become like whipped cream and what (if anything) I can do to make the mixture usable.
Many thanks in advance for your reply.
Molly
HI Molly, You mentioned that you had just made the stronger vat that day. Give it a day or two: more indigo, more lime etc. It takes more time.
Catharine, many thanks for your reply.
After I posted my question I made a second vat with the quantities I usually use. This too went very thick, thick enough to stand the spoon up in. This has never happened to me before, can you throw any light on why it happened yesterday? And why it went so thick.
I tried mixing a very small amount of the first batch with water. In the morning it gave colour. So I took more of the mix and diluted that. It has given splendid strong blue colour all day. Hurrah.
Interestingly, as time has gone on, the mix has become less thick and looking more usable without dilution. I will try it out.
I know it is sorted out, but for future reference, it would be so very useful to understand why it went thick and how to avoid this in future. Also, if anyone else has ever had this happen?
Many thanks
Molly
Hi there,
I tried to make an indigo vat for the first time today using the 1 2 3 step method, and no flowers formed on the surface, although there was a copper sheen. The vat was dying very light green blue colour. I know that the process I was using was reliable and the calcium hydroxide and fructose was the right stuff. The measurements were correct as I had my uni lecturer helping me who had created a successful vat with the same method. The only thing she could think of was that the indigo powder may not have been as concentrated or good quality from where I had brought from. Any thoughts of what’s happening?
Since you just made the vat today….give it a little time. I always make a fructose vat the day before I make it. Stir it several times during that first day. You are correct – the quality of the indigo will affect the vat.
Hello Catharine, your website has been a great source of information and I am very thankful I found it ! I was hoping you could provide me some advice and your expert look on my vat. I am a newbie in indigo dying, followed a 2 days-course with a great indigo master and I decided to make my own vat at home, the same we did during the workshop – 1/2/3 Michel Garcia vat, with fructose. I started it yesterday – 12 liters at 50° C, 50g of indigo. I quite instantly had a beautiful flower and a coppery sheen was starting to show as well. This morning after letting it rest for 24h, the t° was at 26°C, The liquid dark yellow gold and transparent, I forgot to check if the coppery sheen was better or not, I think it wasn’t that obvious, and when i dipped my first piece of coton it turned out very light blue… i tried to stir it (create a vortex), and to reheat it to 50°C -it’s currently warming up- and I don’t know what to do besides waiting, or/if I did something wrong.. as i write this, it’s at 40°, it had just been stirred and showed a beautiful flower but no coppery sheen and the liquid which was golden yellow and translucid is now greenish and rather opaque i guess because I stirred it. Now that I have to wait I am asking myself a ton of questions, I feel like I just met a new boyfriend and that he dumped me already !! Haha. I hope you’ll be able to help 💙Thank you so much for your time and your patience. Coline
Hi Coline, it sounds like you’ve done everything right – you just need to add patience to the mix. A single dip in the vat (you did not mention how long that dip was) will typically give you a nice light blue. Multiple dips will build the color so that you can achieve darker blues but you must wait and oxidize between dips. Also, once you stir the vat, you do need to wait until the lime etc. settles and the liquid become clear once again – before you dye in the vat. There should not be a need to re-heat it.
Thank you so much for your answer ! You were right, patience was the missing ingredient there… I did manage to get beautiful blues afterwards. Thank you again ! Coline
Is the amber colored vat less desirable than the yellow?
No, I don’t believe so.
Hello: I made my first Indigo Vat with Fructose and Lime. I got cute light blues. Do you think I can revive it with the same products? It no longer dyes so dark, it maintains its golden yellow color but more cloudy, and I want to get darker blue in my fabrics. Can I feed my vat with other foods and then return to fructose later? From Chile I give you a big Thank you!!!
I don’t know how old your vat is or how much you have used it. But since it still has a golden yellow color, it may just need more fructose (or fruit syrup) and additional lime.
I got my fructose from nut.com and if has worked just fine apparently. But I recently heard that fructose powder made from corn is not as effective as fructose from fruit. I just went on the nuts.com website to see if I could determine the origin of their fructose. It seems like they are no longer carrying it….searched but didnt find it.
Any thoughts on what fructose powder is made from and whether it matters for the indigo vat??
Fructose, by definition, is a sugar made from fruit or honey. Any of those are “reducing sugars” and will work with an indigo vat. Cane sugar, on the other hand is NOT a reducing sugar. It is the the sugar most of use use on the table and in cooking. It comes from sugar cane. I believe that corn sugar is not a reducing sugar either.