Alder Bark Dyes at Acid and Alkali pH

"Not more bark dyeing, is it, Beaut?" My companion, Elinor Gotland, opened the back door to let out the heat. "It's like a sauna in this kitchen."
"Oh, good, I thought it was just me."
Elinor wiped the steam off her specs and watched as I unbuttoned my cardi and flapped the bottom of my T shirt.
"I thought you were past all that."
"So did I, but the hot flushes are back worse than ever."
"Ah, the Menopause Fairies bring many gifts."
"Menopause Fairies? I never heard any stories about them."
"To be honest, Beaut, not many people have. They just don't get the same media attention as the types that cluster round the crib, getting in all the Christening photos. Fifty years on, nobody brings a camera to anyone's Festival of Changes, but Sweaty Betty the Hot Flush Fairy is usually the first to turn up and the last to leave."
While Elinor was talking, I had turned down the heat under the pots.
"Drat and double drat. I didn't mean to let them reach a full boil."
"That'll be Slack Alice visiting you with her fairy gift of Inattention. What have you got in there anyway?"
"This pot is another silver birch dye. While I've plenty of fresh bark available, I thought I'd have another go at dyeing cotton and see if changing the pH makes as much of a difference as when I dyed wool."
"And the other one?"

"I'm doing another pH experiment, using alder. Had to peel branches for bark, because rainstorms have washed all the fallen cones out of that ditch where alder trees grow."
"You know full well what'll happen when you increase the pH, you've done it before."
"Have I?"
"Yes, last year, you knitted that bag with alder dyed yarn. Then you put it through the washing machine with ordinary washing powder and it changed colour. You remember, washing powders are always alkaline, same effect as soda ash."
"Oh. Maybe you're right." 
"Goofy Gladys is the Memory Fairy."
"I don't think I like these Menopause Fairies. Are there many more of them?"
"Well, there's Gladys' best friend Grace, who makes you bump into things. And watch out for Gloria, the Gravity Fairy, who grabs any dangling parts ..."
"Enough. I shall combat Gloria with an underwired bra."
"You'll need a full metal jacket for those, Beaut."
I heaved a sigh and turned back to my dye pots.

Two hundred grams of alder bark had been soaked in a bucket of water for a week. Testing with a strip of indicator paper showed fermentation had made the water mildly acidic at pH5. After simmering for an hour, I left the bark in the pot and added three 50g skeins of wool yarn, simmered them for an hour and left them to cool before taking out one skein.

This time, I thought I would alkalinise the dye bath using wood ash, so I took a tablespoonful from the grate and put it in a jam jar with some water. Once the ash had settled, the fluid tested strongly alkaline. Unfortunately, you would need far more than one jar full to alkalinise 10 litres of dyebath, so I had to add some dissolved soda ash too.
With the vat brought up to neutral pH 7 and simmered again, the wool wasn't changing colour perceptibly, so I added more soda ash to make it mildly alkaline at pH 8.

After the pot had cooled, I took out the second skein, increased the pH to 10 and simmered one more time. Here are samples of the dye baths at each pH, though rain wrecked the indicator strips before I could take the photo.

Alder bark dyed wool yarn at pH5, pH8 and pH10

The dye bath still looked dark, so I added a slug of iron water and simmered another 100g skein of wool, getting a saddened version of the alder dye colour which is shown on the far right. All the skeins were left to dry for a week after dyeing, then rinsed separately in several changes of water.

Knitted into stripes with some undyed yarn, a small swatch did not run or change colour when washed with pH neutral washing liquid in the washing machine on a 30 degree wool cycle. I've found both silver birch and alder bark dyes seem washfast and stable as long as you don't mess with the pH after dyeing. I've taken on trust the idea that the tannin in bark means that wool doesn't need to be mordanted before using bark dyes. Which is confusing, because tannins are supposed to be part of the mordanting process for plant fibres like cotton, but are not supposed to be effective mordants for animal fibres.

The All About Bag I dyed with alder bark and cones has got rather battered over the past year. It wouldn't ever have been quite the same colour as the new skeins, but looking at it now, I'd say it has proved lightfast and I am confident that whether that is due to tannins or not, no premordant is needed before dyeing wool with bark.
My companion found me comparing the old with the new.
"Ooo, super duper, once again you have discovered that alder dye is brown and even more brown when it is alkaline."
"I think the colourway is rather lovely, Elinor. Even the beige from the acidic dye bath."

"You'll be wearing elasticated slacks and a camel cardi next."
"So what if I do? I'm happy."
"Ah, I see you've met Frankly."
"Frankly? Bit of an odd name."
"Well, Beaut, she's an odd fairy. Whatever you called her, Frankly wouldn't give a damn, a toss or even a flying fuck at a rolling doughnut. She'd live in a boiler suit, if it weren't for the trauma of going for a pee."
"I like the sound of her much more than Sweaty Betty and Goofy Gladys."
"Fair play, she's, how can I put this ... unconventional. Alternative. You'll remember from the fairytale christening stories, there's always one fairy who appears at the last moment with a gift that subverts all the others. As far as the Menopause Crew are concerned, that's Frankly."