Tag Archives: potassium aluminum sulfate


Salts are ionic compounds that result from the neutralization reaction of an acid and a base.  Double salts are compounds obtained by combination of two different salts which were crystallized in the same regular ionic lattice. An example of a double salt is alum.  Having an extra charged particle allows it to bind well with both the dye and the fibre to which the dye is being applied.  This process of bonding in dyeing is commonly known as mordanting.  Note that double salts should not be confused with a complex compound. When dissolved in water, a double salt completely dissociates into simple ions while complex compounds do not, the complex ion remaining unchanged in the later.

potassium aluminum sulfate

True alums have commonly been recognized as double salts of aluminum, such as potassium aluminum sulfate (left) –  KAl(SO4)2.

aluminum sulfate

Aluminum sulfate (right) – Al2(SO4)3 – is commonly known as an alum, although it is not a double salt. Aluminum sulfate is the result of the refining process of bauxite which is the raw state of aluminum ore. During this refining process sulfuric acid is used to remove most of the iron and silica present in bauxite.

The difference between these two may be subtle but may drastically show different  dye results.Test the mordant with the dye you want to use. Study the Material Safety Data Sheet (MSDS) to determine if the aluminum sulfate you use has iron in it or is refined with potassium.  Iron will also affect the dye’s outcome.

Additionally, the type of pot used in the dyeing process can also affect the dyeing outcome.  Differences can happen whether you use stainless steel, aluminum, or iron pots during mordanting and dyeing.

Today I found a source of aluminum sulfate for less than a dollar a pound and reserved a 20 kg. bag with which to experiment in the coming weeks.  Its MSDS will be telling.  But even in the event of its containing iron it may have a use.  Another common source for potassium alum is an Indian grocery store…look in the personal hygiene section for antiperspirant/antiseptic/aftershave bars – these are often made from potassium alum.  Trying them as a mordant would be more than worth the effort.

Alum And Mordanting












Dyeing Llama Fibre With Haskap/Honeyberry/Edible Blue Honeysuckle/Lonicera Caerulea

This post tells about my first dyeing of llama fibre using Lonicera caerulea (haskap) berries.  The llama fibre is unwashed white from one of my own llamas, and the berries are from the Tundra selection of University of Saskatchewan haskap grown in my own orchard.

I set up this test using two sets of four samples:

  • 1 – The first sample remained dry and undyed as a comparison.
  • 2 – The second sample was dyed, but was not soaked or mordanted beforehand.
  • 3 – The third sample was prepared by water soak preparation only.
  • 4 – The fourth sample was prepared using a traditional salt mordant (NaCl).

Two samples were prepared from each.  This will allow a comparison from each  treatment before and after they dry and one is subsequently washed after several days in order to determine colour-fastness of this berry’s properties.

This procedure allowed me to compare later on as a base-line comparison of the simplest sort.


Haskap is a newly cultivated berry that found its way to North America in the 1990’s and is now being intensively bred and selected for at the University of Saskatchewan.  Haskap is the name applied to a superior selection of genotypes of Lonicera caerulea.  These plants are commonly known as edible blue honeysuckles, and also have been marketed using the name of Honeyberries.  Their berries come from flowers that can withstand a -7C freeze and still produce fruit, and the plant is still viable after winter temperatures drop below -40C.  It is truly a northern plant and modern plant origins can be traced to Siberia, the Kamchakta peninsula, and the northern island of Japan.  The berry’s meat itself is coloured a deep, rich burgundy; it stains anything with which it comes into contact a bluish-purple.  The stain can be removed by citric acid.  Otherwise it is very difficult to remove.  I can find no reference to its use as a cloth dye using a simple internet search.  We currently have almost 3,000 plants in our orchard, parts of which are just now coming into full production.


  • Since aluminum and iron can affect the the dying process (serving as mordants themselves), all utensils and pots used were made out of stainless steel.
  • The salt mordant (fixative) consisted of 1/16 cup of salt to 1 cup of water (1/2 cup of salt to 8 cups of water for larger batches).
  • The dye itself consisted of 1 cup of berries to 2 cups of water.  This was brought to a boil, the berries crushed, the mix simmered for an hour with the lid on, and then strained.
  • The third and fourth batches of fibre were simmered for an hour before being dyed.  The third batch was simmered in water alone; the fourth batch was simmered in the salt mordant.
  • All were then simmered in their own respective stainless steel pots with strained dye, again with devoted utensils.
  • These were then set out to dry.


Raw llama fibre…note white guard hairs…
Unwashed white fibre to be used for dyeing…
Fibre opened up...
Fibre opened up…
Frozen Tundra berries to be used as dye...
Frozen Tundra berries to be used as dye…
Fibre sample to be used for four lots, each with a baseline control...
Fibre sample to be used for four lots, each with a baseline control…
Berries in water before boiling...
Berries in water before boiling…
Lot #3, simmered in water only...
Lot #3, simmered in water only…
Lot #4 simmered in salt mordant (these immediately took water compared to lot #3)…
Fresh out of the dye, labeled according to their lot…
Towelled off, the light is not so good inside and late in the day to show its true colour…

Tomorrow I will wash one piece of each lot and see if the dye remains fast or not.  These will serve as a baseline for future dyeing, particularly in relationship to mordants such as alum (potassium aluminum sulfate KAl(SO4)2·12H2O).