Caseine Printing from the Kitchen Sink
Prepared by Dr.Selby Markham
Casein printing comes closest to a process that can exist in the world of the kitchen sink chemist.
I suggest that if you have a source of skim milk (dried or fresh) or full cream milk (dried or fresh), vinegar or citric acid, sodium bicarbonate, borax or cloudy ammonia you are well under way. With a selection of these ingredients in your household cupboards you can brew up your caseinate in the kitchen sink for next to nothing and in no time flat. Then you have to buy a bit of Dichromate to bring it all together. There are articles in this series for making sodium caseinate and ammonium caseinate.
My interest in this basic approach to doing casein printing derives from the problems in Australia of sourcing the ingredients that are quoted in most on-line recipes. Clear Ammonia can be used to make explosives and is, consequently, hard to get. Ammonium Caseinate is not listed for any Australian chemical source in sensible quantities. Even casein powder is a problem because you have to buy such large quantities. Sodium Caseinate is the only readily available casein salt.
These issues are compounded my tendency to enjoy doing things from scratch.
But casein printing is also a bit mythological where people have methods they will not divulge and others are vague and indefinite. And this is compounded by the lack of accuracy in measurement methods – cups and grams, ounces and millilitres.
Myths about casein and caseinates
You must use skim milk
The technical reason that skim milk is preferred is that the shelf life of the casein is reduced when there is fat around. Exactly what the milk fat might do in caseinate printing I have yet to find out, but prints I have made with full cream casein have been quite OK.
You use dried milk
Dried milk is convenient but should you have some out-of-date liquid milk , which has not gone off, you can use that. Using fresh milk is very wasteful.
You must not use cloudy ammonia
It is obvious that cloudy ammonia has a pollutant, namely soap. I have yet to find any difference in performance between ammonium caseinate made from cloudy ammonia versus that made from, for example, ammonium carbonate.
Casein has a poor shelf life
This is true if you don’t dry it. But drying home-made casein is very easy. Rehydrating it is also quite easy as you will see in the notes that follow.
Cottage cheese is better
Maybe, but cottage cheese is simply good quality casein. More importantly, what is called cottage cheese depends in which part of your country, or which part of the world, you live.
Making and Drying Casein in the Kitchen Sink
This method of preparing casein came from an article posted on the University of California at Davis web site. Their Dairy Research and Information Centre has given the neatest and most effective method I have found. There are variations on this but I have taken their method and given it a significant level of small scale functionality.
https://drinc.ucdavis.edu/dairy-food-sciences/preparation-casein-skim-milk
The important points made about the process are:
- Casein production must be done with warm (about 400C) milk. This helps produce a solid, completely separated out lump of casein. No more messy filtration through stockings.
- The amount of acid used is important because too much acid will cause part of the casein to redissolve.
Also, if the acid is too strong then some of the casein is likely to start to redissolve. - The speed at which the acid is added is important in getting a good lump of casein.
- The mix must be left for a minute or so between acid additions so that the curd can stabilise.
- The production of casein in this way (but not including drying) will take about 20 minutes. Patience is needed. But the result is simpler to handle because you do not have to filter and consolidate a loose mass of curd through tights or cheesecloth.