We havn’t posted for a while – the thing is, that when you have a lot of projects going on, there is little time left for bloggning..!
Our main priority now is to find a decent cheese vat. We are rebuildning a part of the barn in order to make a milking facility for the goats, but it is time to get things going when it comes to the actual cheese making. To be continued… Until then, here are some photos of when we attended a course with the french expert Michel Lepage, hosted by Eldrimner.
The forests have always had a crucial role in the Swedish economy. They have given us fuel, building materials, paper and chemicals, but also a habitat for a rich wildlife, and highly valued recreational areas.
In old times, cattle was often kept in the forest. Feeding on leaves, herbs and barch, the forest gave an addition to a scarce feedstock, but modern breeds are no longer able to both survive and give milk or meat on such frugal diet.
Goats on the other hand, has a much more efficient digestion, and is actually the only domesticated ruminator capable of digesting wood fibres and lignine into sugars. So when your goat heard browses the forests for brush, barch, sticks and spruce needles, and then returns to the barn in the evening to get milked, you actually conduct a refinement process where the input is cheap and abundant cellulose, and the output is exclusive and nutritious milk proteins. The production of proteins for the human diet through livestock handling is often referred to as unfriendly to the environment, with high water consumption and much larger areas needed than for the equivalent calories from vegetables and grain. The conversion of cellulose to go at milk proteins and buckling meat does not have the same problems, since the forest mostly grows on improductive soil, suitable for nothing else than forest. The forest does not need to be watered nor fertilized, neither does it suffer from pests and draught as easily as field crops.
Even if we only milk one of our goats for the moment (and she is a low producer that give approximately half of her milk to a very hungry kid when they are together in the pasture), the milk bottles is filling up the fridge faster than we can consume it. We’ve already quit buying milk for drinking, coffee and cooking, so the next product to make ourselves will be yoghurt.
The process is rather simple, take some milk, pasteurize it if you don’t trust your hygiene, add bacterias and keep the temperature at the optimal level for as long as it takes for the bacterias to consume all accessible lactose and lower the pH to uncomfortable levels.
You can do this in your oven, but the temperature control will be crude, which results in runny and uneven yoghurt. There are yoghurt machines, not that expensive, that controls the temperature very well, but they don’t know when to turn themselves off, so you still have to watch it, or set the timer out of your best guesses.
Since my Diy wireless pH-sensor gives me the two variables I need to control the process (temperature and pH), I figured that I only needed a heat source. Then I found something even better at a second hand store; a portable 12V peltier cooler/heater from Waeco, made in the early 90’s, featuring such elegant solutions as switching between heat and cold by turning the electricity cord, thus switching polarity.
This makes the perfect completely automatic yoghurt maker, since it both keeps the heat at an even level, and when the right pH is achieved, cools the yoghurt down to fridge temperature. Just throw in some milk and culture in a jar (or a teapot) and leave.
The controller is very simple. Since the only functionality needed that the waeco box didn’t handle, was the ability to turn on and off and switch polarity remotely, I connected a L298b motor driver and a NRF24L radio to an Arduino nano. The L298b module is normally used to turn DC motors forward and backward, but that could be applied to the peltier element in the box to make it hot or cold as well. Unfortunately, the L298b was only capable of 4 amps in throughput, and the waeco transformer supplied more even though it was specified for 4, resulting in a very hot chip. The solution was to use 2 L298b in parallell. Power cables as well as signal cables to the arduino.
The chips were still hot, but with a cooling fan from a PC chassi, they are now cold and very cool. I connected the fan to the input side to let it consume some power and make it easier for the L298b. That means that the fan is always on, which might be unnecessary.
The Arduino code for the controller is also really simple. I used the mysensors.org sample code for relay and made two adjustments: increasing the numbers om relays to at least 3 (I actually enabled 6, as there might be need for using the second channel on the L298b in the future, but for this functionality, you only need 3) and enabling pwm on the pins that controls on/off. I haven’t used pwm for anything yet, but that will allow me to control the current from the L298b output (speed, heat etc.).
The logic is placed in the home automation system I have running on a Raspberry pi. It is currently Fhem, but any system with support for the Mysensors library will work. Fhem is a quite complex system with lot of forum material in german, but if you are comfortable with both German and Perl, there is no more powerful home automation system in my opinion.
The controller presents itself in Fhem when the gateway is in inclusion mode, and this is the fhem.cfg code that is generated (with som additions):
The yogurt culture I am using prefers a temperature of 43 C and I will let it work until it has reached a pH of 4.20. I’ve hardcoded those levels in my config file for now, but an improvement will be to create a device that changes these values.
I want the machine to:
Rise and hold the temperature on 43 C.
Do that until pH has dropped to 4.20
Then cool it down as much as possible
That is achieved with the following code in fhem.cfg:
Worth mentioning is that the pH-sensor is called MYSENSOR_118 and its temperature sensor reports as temperature, while its pH-sensor reports as temperature1.
So this is the result. The red line is temperature, starting at fridge temperature at 6C and rising steadily to 43C where it plans out. Meanwhile the green bars representing the pH goes from 6.5 to 4.4 (at the time of the screenshot).
Obviously, the Waeco box isn’t made for heating, rather than keeping a temperature. The slow rise of about 8-9 degrees/hour making it 5 hour until optimal temperature is reached, is not acceptable. Heating the milk before putting it in the box is one easy solution, another is to never cool it down and let it go directly from the udder to the box.
When you search the internet for information about goat milk, it’s easy to think that you’ve discovered a miracle food, that the rest of the stupid western world either know very little about, or has been taught by religiously induced habits and commercial efforts from “big dairy” to despise.
It’s also tempting to copy all these tributes to goat milk straight off, and tell all your friends to start drinking goat milk in order to cure some diseases, or at least lower the risk of catching them. I almost started doing that, when I realized that I had no clue if it really was true, so I decided to go to the sources. The trick is, when it comes to stories about functional food and other miracle products, nobody is citing any sources. Eventually a study is referred to, but there seems to always be discrepancies between the field of study, and the point of the article. Otherwise, anecdotal evidence is popular, people who drink goat milk report that they reap great benefits like not having cancer or completely stopped passing gas.
What the field of goat milk research actually seems to boil down to, are some deductions that can be made from studies of the health effects of cow milk. We know what is bad in cow milk, and if goat milk doesn’t contain those components, we can assume that goat milk is better at least. Right?
Beta-casein and the correlation between cow milk consumption and severe diseases
The milk protein beta-casein, that is a key component in cheese, exist in two genetical variants, A1 and A2. The A1 variant seems to bee a relatively modern morph that accidentally has come to follow the trait of high milking ability in cow breeds like Holstein and Red cattle, and thus the dominant variant in industrialized milk and dairy products.
According to several studies, there is a correlation between high A1 consumption (like in Sweden and Finland), and diseases like diabetes (I), autism, schizophrenia, ischaemic heart disease and bowel inflammatory problems.