Nordic Tofu: preliminary experiment

The idea:  eat your lawn

This fall I attended a meeting with some colleagues from Aarhus University, where they are working on extracting protein from grasses and forage material, such as clover, to produce feed for pigs and chickens, as a local replacement for imported soy feed for animals. this got me thinking about my own protein intake (vegetable based), and where that comes from. While a vegan diet is 10x more efficient then a meat based diet (this is a rule of thumb that it takes 10 kg of plant based food to produce 1 kg of meat), we still import soy from other countries, making us dependent on global food streams. This local sourcing of animal feed got me thinking, why not cut out the middle pig, and extract and eat the protein ourselves?  some of us that are lucky enough to have a garden and a lawn, so why not extract protein from our grass clippings, and eat them!  the idea for ‘nordic tofu’ was born.

Process development:  Tofu dreams

the process as proposed by the group at Aarhus University is fairly straightforward, with pressing the liquid out of the grass (the majority of the protein ends up in the liquid fraction), heating up the liquid to denature the protein, precipitating out the protein fraction (either with salts/ethanol or with a lactic acid fermentation to reduce pH), and then drying and pelleting it to make feed for animals.  However, for human consumption, we don’t want to eat dry pellets, so I proposed extracting the protein rich liquid, and then using this protein liquid to produce a type of ‘tofu’.  tofu is produced by boiling soybeans (making soy milk), adding a coagulant (usually magnesium chloride), filtering out the coagulated protein liquid through a cheese cloth, and pressing it in a press to remove excess water.

Based on this process, I sketched out a method for producing our nordic tofu in the lab.

The process looked roughly as follows:

step 1:  harvest grass.

step 2: Juice the grass

step 3: boil the juice on the stove in a pot

step 4: add some magnesium chloride (dissolve a half teaspoon in some water, and add, stirring slowly)

step 5: filter through cheese cloth

step 6: press the cake

step 7:  cook and eat!


From Idea to Action:  Project night

I mowed my lawn for the last time and collected the clippings.  Being late in the fall, there were also some leaves mixed into the grass, but I tried to pick them out as best as possible.  however this would probably be better done with fresh spring grass.

I gathered a interested crew of biohackers, and we went down to the lab to set about extracting the protein.  it turned out we didn’t have a juicer, so we tried just using a hand blender to break up the grass.  after breaking the hand blender and getting some help repairing it from the Labitat guys (hot glue gun for the win!), we were able to break down some of the grass, however this step was not ideal.

we then tried to squeeze the juice out through a cheese cloth, but there was definitely a significant amount of grass fiber that went through along with the liquid.

Once we got some liquid, we heated it up on the stove, before adding the magnesium chloride.

It was awesome to see the protein fall out of solution!  we filtered again through cheese cloth, and pressed it using our hands and then put water in a bowl on top of a pasta strainer to put pressure on the mass.  The finished product looked like this.

We then fried it up with soy sauce, and put our most gastronomically advanced experts on the the task of taste testing our creation.

Results, Discussion and paths forward

To be honest, the results were a bit mixed. There was a strong grassy and chlorophyll like taste, which is not entirely pleasant. there was also a significant amount of fiber in the tofu, which gave it a grainy texture in the mouth.  It was definitely edible though, and no one reported stomach issues the next day.  Success!!

Notes for next time:  First, use fresh grass, and preferably spring and summer grass.  this grass had been growing a month and was at the end of the growing season. I think it is important to run the grass through a juicer, thereby removing all of the fibers, and getting a cleaner protein product.  It was also suggested that we try and extract or break down the chlorophyll (which is itself a useful and high value food product, check your local health food store). Chlorophyll is soluble in ethanol (Ref needed), but this might also effect the protein.

Either way, this is an interesting and new source of protein, but it needs some more work to get a more palatable product.  Keep your eyes on our events page for a group experiment night where we further work on this concept in the spring, once the grass starts growing.  Thanks to all my co-hackers and taste testers!

photos and videos from the project night