I have been doing a lot of tests with yeast recently and notice the more dried yeast used the more color there is in the water. That could be due to the extra yeast, or it could be something in the dried yeast itself. I looked up the ingredient that is in the yeast I use, E491 or Sorbitan monostearate. From my understanding of dried yeast it is live cells of yeast wrapped in dead, dried cells. On top of this is this waxy type substance, Sorbitan monostearate, which further protects the yeast from oxydization/moisture increasing storage life and aiding in quicker rehydration.
I found one source for amount of E491 in dried yeast. http://abmaurianz.com/au/SiteMedia/w3sv ... 0Yeast.pdf" onclick="window.open(this.href);return false;" rel="nofollow . They state it's around 1% in their product. I found a patent for this process of adding E491 to the dried yeast to help it store longer and rehydrate quicker, they state it could be anywhere from 0% to 5%. http://www.google.com/patents/EP1499197A2?cl=en" onclick="window.open(this.href);return false;" rel="nofollow
Wax-like creamy white powder.
Sorbitan monostearate is an ester of sorbitol and stearic acid.
The sorbitol end of the molecule is very soluble in water. The stearic acid end is soluble in fats. These properties make the molecule very good at making emulsions of oil and water.
It is sometimes known as a synthetic wax.
Although I am not a chemist, and I hope someone can correct me if I am wrong, once put in the water the sorbitol would dissolve leaving the stearic acid floating around in the water, potentially able to be used by the yeast, potentially also clouding/coloring the water to some extent. --- This is wrong
Here is a picture of dried stearic acid.
This is exactly the color I see in my wash after the yeast settle. Is it a coincidence?
Last edited by hoochlover on Tue Oct 13, 2015 10:06 pm, edited 1 time in total.
I received an email stating the yeast (instant bakers yeast) I use has around 1.5% sorbitane monostearate. I'm running an experiment at the moment to determine if multiple dilutions of the yeasts solution remove this coloring. Another possibility is the dead yeast cell contents that is present in the dried yeast is somehow contributing to this as well.
I just put 20g of yeast into 200ml of 30C water with a tiny bit of sugar to see what would happen. The yeast started to settle pretty quickly after consuming the sugar, which took a couple of minutes. There was this top layer of "something" floating there that was not sinking. Like a mixture of yeast and oil floating on the surface, I soaked it up with a paper towel just like you would oil floating on a surface. I've never just put yeast in water without much sugar before to notice this.
The space between the surface of the liquid and where the yeast has settled is still strongly colored though, I have tried one dilution already on another batch and it's less colored in that one. It's not the color of the yeast which is why I suspect it's something else, not just floating yeast.
This is a microscopic picture of dried yeast. You can literally see this waxy E491 / Sorbitane monostearate coating on the dead, dried cells which are surrounding the live ones we cannot see.
This is a less magnified version of the shape of the little dried yeast granules. I guess they are this shape from the industrial process used to make it. Looks like they are squeezed through a small hole and sprayed on a surface.
