Dye Experiment: What water works best?

I posted a few weeks back about visiting my friend, Beth, and dyeing some yarn with her.  I was so surprised by the color differences I got with dyeing at her house compared with the colors I got by using the same formulas at home.  It could have been the wool difference...we used BFL at her house and I used merino wool at mine.  Different wools will absorb dyes differently which makes sense given they have different fiber characteristics.  Beyond the wool difference, I felt that maybe my tap water also had something to do with it.  Where I live, we have extremely hard water!  Since we don't have a water softener, we have to buy drinking water, use shower filters, and filter our tap water.  

I decided to do an experiment with four kinds of water to see what would happen when I dyed mini-skeins with Kool Aid.  

The four kinds of water to test were:
1.  Tap water
2.  Pur filtered water
3.  Distilled water
4.  Reverse osmosis drinking water purchased at Earth Fare grocery

The first thing to do, was to create mini-skeins.  I used some Lion Brand Fisherman's wool for this experiment since it is too rough for me to knit with it.  I made four, 10 gram mini-skeins by wrapping the yarn around a sock book and then measuring on my scale.  

After labeling the jars, I put the mini-skeins into each jar, and put 2 cups of the appropriate water into the four jars.  I let the yarn soak in the water for an hour or more to help it absorb the color quicker when the time came to add the Kool Aid. 

Before adding the color, I removed the soak water and squeezed out the excess water in the mini-skeins.  Next, I dissolved 2 tsp of cherry Kool Aid in 2 cups of water, and added it to the first jar.  I continued to do this, making sure to put only the designated type of water into each.  I then put the four jars into my large canning pot onto the stove.  Using tap water, and being sure not to get the water into the jars, I added enough water to cover the jars (just 1 1/2 inches below the rim of the jars).  Then I turned on the heat to medium high, and let it cook.  

I made sure to put the jars in the canning pot in order of where I have my sticky notes since I didn't know how to label the jars before putting them into the water pot.  

Cooking the yarn!  I let the water get to a rolling boil, then turned the heat down to medium for 10 min, covered the pot, and turned it off.  I didn't open the pot back up until many hours later.  Once cooled, I was able to remove the yarn from the jars.  

The color absorbed the quickest in the reverse osmosis and the distilled jars.  Here's a picture of the tap water jar.  You can see that it has not fully exhausted.  I could have put it back on to cook, or put it into the microwave to absorb, but since it was 11pm at night, and I was tired, I decided to let it go.  This is an experiment anyways...if it didn't fully stick to the yarn, it doesn't matter.  

Here is a picture of the reverse osmosis water jar.  The water fully exhausted!  

The distilled jar also fully exhausted.  The Pur filtered water (no pic of it here) did not fully exhaust.  Showing that the tap and Pur filtered water needed more heat and time than the reverse osmosis and distilled waters.

I hung the mini-skeins on my drying rack and kept the labels by each one.  They dried overnight.  

When looking at the final mini-skeins, it's hard to distinguish each one based on color alone.  I tried to capture the difference with my camera, but it's so subtle, I think you can only see it in person.  The reverse osmosis and distilled water skeins are slightly darker than the tap and Pur filtered skeins.  If I were to wash them now, I'm pretty sure that the tap and Pur filtered would run color given that they did not fully exhaust in the dye bath.  The reverse osmosis and the distilled water skeins exhausted completely, and should be colorfast now. 

Now, I'm not a chemist, but my husband (also not a chemist) and talked this through, and here's what we came up with....

I think that by washing them in my tap water, even the colorfast ones, some dye will come out.  I have washed commercially dyed fibers before with our tap water, and some color always runs for me.  It has to be the hard water!  The calcium in the water would affect the pH level, and therefore mess with the acidity of the colors.  When dyeing with Kool Aid, the citric acid in the Kool Aid packet is the acid needed to make the color stick to the yarn.  When you add hard water (which has calcium as a base in it), it will neutralize the pH of the citric acid, making it harder for the color to absorb.  If I had added more citric acid, or even vinegar, to increase the acidity, the color probably would have exhausted completely in the tap and Pur filtered water jars.  

I'd love to hear from you if you have any thoughts or knowledge on this topic!  

This has been a very interesting experiment, and I've decided to start using distilled or reverse osmosis water when dyeing instead of our tap water or Pur filtered water.  I would like to redo the experiment sometime with a pH monitor (something I don't currently own).