July 13.
Melanie has been a great support for this project. She has been regularly looking at our process and it feels like she is “walking with us” for this very interesting and experimental road.
As we are struggling (or rather, taking long way) for the fermentation of the vat (vat 1 log, vat 2 log) we have been constantly thinking and discussing what we can do to it. The problem of each vat is the following:
Vat1: It started off very good, but after the 8th day, PH meter got strange and it started to show lower PH… so I added lime to counter the drop of the drop of the PH. This is because when PH is lower than 10, unwanted bacteria can grow in the vat and this is very bad. As a result, before I noticed that the problem is the PH meter, I added way too much lime and the vat PH became way too high (PH13!) and the activity of the bacteria stopped.
Vat 2: we started the vat 2 after the vat 1 started to have the problem, thinking at least we can manage the 2nd one. But we made some mistakes in the beginning of the vat process. I decided to follow the recipe more strictly this time. The recipe we used is from the book “Journey into Natural Dye”. In this recipe, it uses quite a lot of lime in the beginning when you first wet an kneed the Sukumo, but they also lower the PH of the ash water to PH10.5. We used ash water (over PH12) at 50 degrees to kneed the Sukumo, but we did not reduce the amount of the Lime. (In the case of the first vat, I did not even add this lime at all) and when we are topping up the vat with another 20L, the gas cooker we were using was too weak and it could not bring the water hot… so I ended up adding 30 degrees ash water. Probably it was too low to activate some of the bacteria we want to promote (I did not know then, but some of them need over 35 degrees to be active). As a result, it seems like bacterias in vat 2 is not fully awakened and the PH of the vat is staying over PH12 since the beginning and never came down.
We have been giving a lot of effort to bring the PH down. We increased mixing timing to 3 times a day so the air liking bacteria gets more oxygen and get active… replacing vat water with lower ph ash water to bring the PH down… but so far no success. Vat 1 PH is now finally down to just about PH 12 or 11.9. but not a significant change.
On the July 12th, I and Madlen had a chat with Melanie. We have been discussing the last few days over the text message about adding working vat (I have 20L working vat at home that I can give to the project). There is a vat making technique called Sasoi-Date (enticing fermentation), to introduce old sukumo at the beginning of the new vat making. This way, the bacteria in the old sukumo is in the new process from the beginning and it helps to start a new vat. We are not doing it at the beginning, so it is not exactly the method of Sasoi-Date, but it could help… and theoretically it sounds like it should work.
The risk of doing this is that vat/bacteria does not like sudden change of the environment. So, it could be that the working vat bacteria just dies as it is added to another vat, which is a lot bigger than itself. Also, it has been living in my bathroom, which has much more stable temperature, is going to adapt to the Hütte, which temperature changes much more drastically.
Melanie shared her experience of using her 20L working vat to her 200L vat that stopped working. She reduced the 200L vat to half size, and added her 20L vat. It started to work for a while then it got very weak. 20L vat has only 1kg of Sukumo, while 200L vat has a lot more… so if 20L vat added in it is not influencing the whole mass of Sukumo, it eventually become very weak.
And Melanie had some new information after talking with her friend Kato, who is also an indigo dyer. He had a complete different ideas: 1) to lower PH, you can actually add cooked hot water. As water is ~PH7 it should lower the PH more significantly 2) stir/mix much less times. just once a day. This will actually lower the PH. 3) adding vinegar to lower the PH is a bad idea (this is opinion of Melanie as well!)
We discussed if we should go ahead and add the working vat, or just lower the PH with cooked water and wait for a while longer. On one hand I am tempted to add the vat, as it feels like I am doing something actively… on the other hand, often “waiting” is what is needed for the fermentation. we are waiting, but bacteria are doing something. Melanie is in general, taking an approach of “doing less, change less environment”. She told us “every change you do, everything you add will also has consequences in the future vat as well”. So it may save the current situation but it could be introducing bi-product in the vat that changes the development of the vat environment in longer term. It is like the climate change in a small universe. I, the human adding things with my “clever” logic to make it better… but we have to think of the longer term as well.