I apologize for the sweets, like dulce de leche and fruit preserves below. I think kids that grow up not eating sweets, given only healthier options, won't be adults who think dulce de leche is God's gift to humanity.

Something to think about to use less energy…
https://www.builditsolar.com/Projects/Cooking/cooking.htm
https://solarcooking.fandom.com/wiki/Solar_Cooking_Wiki_(Home)
https://permies.com/t/65217/DIY-Solar-Oven

Human nature wants the fanciest equipment to do something simple for an imperceptible or fantasized gain in quality. Investment in such equipment gives capitalism an orgasm: consumption for the sake of consumption. Such is the case for wine and coffee snobs.

By contrast, an engineering discipline seeks a simple solution.

Cold brew requires the least energy consumption. Coffee grinds soak/steep in water for 12+ hours.

I understand it's also healthier. Variables Affecting the Extraction of Antioxidants in Cold and Hot Brew Coffee: A Review, Yust, Wilkinson and Rao 2024

Flawed comparison of cold and hot brew

Up for research: What ratio of coffee to water can be used for the brew? Is it ok to add little water to make a concentrated expresso? Is the extract different if you use more water?

I had the wrong impression that coffee ground sufficiently fine would dissolve in water. They don't. Also the course grounds are no fun to chew for added fiber.

With the manual grinder I'm currently using, all the grinds aren't exactly the same size. The finer ones add a nice texture to the liquid as it slides over the tongue. This gives me something to shoot for.

A positive to Turkish grind is that you get a very fast steep rate. If you grind the night before and leave soaking at room temperature, it's ready by the morning.

Using an overpriced consumer-oriented manual Turkish coffee grinder is too much time and work. If you want Turkish grind, I suspect a flour mill would be better.

A good electric coffee grinder has to output a bunch of different particle sizes, leading to a master-of-none situation.

microtrac.com

A flour mill grinds with a tighter distribution size, with negligible number of particles over 300 μm. Evaluation of Flour Particle Size Distribution by Laser Diffraction, Sieve Analysis and Near-infrared Reflectance Spectroscopy, G.A. Hareland 1994 download

Unfortunately, a decent grain mill like the Mockmill starts at $340. At one point I was wondering what do Turkish people use. Turkish people mostly don't grind their own coffee. They buy Turkish grind from the store, or they go to a coffee house.

Update: Coffee Grind Size Chart, honestcoffeeguide.com

Flawed storage experiment

1 liter of whole milk
1 tablespoons of stevia / erythritol mixture
1 tablespoon of sugar
100 ml of cream (optional)
1 vanilla stick or vanilla extract (optional)

1 teaspoon baking soda (optional)
10 grams of unflavored gelatin (optional)

Really, you only need milk and sugar. That's it. I like my dulce de leche more creamy, so I add cream.
Sweeteners can be added to taste. I find any store bought dulce de leche overly sweet. They add as much as 1/2 ratio of sugar/milk. Practically ruins the experience.
Erythritol crystals melt at 121 degrees celcius, but do not reduce (chemistry).
Gelatin is to make the dulce de leche denser with a shorter cooking time. It's cheating and not necessary.
Baking soda helps reduce lumps in the dulce de leche. Some recipes have it, but I am suspicious of this ingredient on the end outcome.

OVEN ATTEMPTS:

I have attempted using an oven to make dulce de leche, because I thought heat is more evenly distributed, and will keep the mixture from burning on the bottom of the pot. Milk has a boiling point of 95 degrees celcius, however, you can set the oven slightly above this temperature. Maybe an infrared thermometer would help to check the temperature of the milk surface.

As opposed to an oven, cooking with a pot on top of a flame can superheat the milk adjacent to pot surface, causing it to boil over and spill from the pot. The bottom of the pot in an oven is unlikely to reach such a high temperature as that of a flame.

In an oven, the top surface of the milk is at more of a danger of burning from the top coil of the oven, from radiative heat transfer.

Also, if you set the oven temperature too high, the fat will separate, or perhaps break down, and you won't get a creamy mixture: just runny oil with chunky parts.

For some reason, it takes FOREVER in the oven. More than 5 hours. Is the moisture not allowed to escape, thus keeping the water in the milk from evaporating?

NORMAL INSTRUCTIONS:

Place milk, cream, and sugar, and the optional vanilla, in a stovetop pan, and bring to 90 C.
At 90 C, you can optionally add baking soda, and optionally add gelatin.
Stir every so often. You will require progressively more stirring as the milk thickens. You can also turn down the temperature as it thickens to reduce a temperature gradient between the surface and the inside of the dulce de leche. Some people add marbles to encourage self mixing, and perhaps they also create a surface at a higher temperature than the surrounding dulce de leche. I suspect that commercial production of dulce de leche involves ovens with automatic mixing.

Raw milk and milk cream, stirred with powdered milk to thicken, sweetened with stevia and erythritol. Not because it tastes better, but because male cooking means less effort.

Raw milk 60ml
Milk cream 20ml
Powdered milk 100g
10 drops of stevia

Full instructions for making raw milk yogurt at:
https://nourishedkitchen.com/raw-milk-yogurt

I'm going to try adding culture to yoghurt at room temperature, rather than 110F (43C) as suggested. Or maybe I'll use my oven.

Which bacterial culture should I buy?

Fresh milk, even if refrigerated, starts to turn sour within 2-3 days. Could you preserve milk by having it turn to yogurt instead?

Update: found these articles:

MESOPHILIC YOGURT: MAKING YOGURT AT ROOM TEMPERATURE, Ashley Adamant 2021
How To Activate Your New Mesophilic Yogurt Culture, positivelyprobiotic.com

If one were to genetically engineer yogurt bacteria that proliferated at 4 degrees Celsius, you could put some in fresh cow milk and place the milk in the fridge. Instead of having refrigerated milk go bad if it isn't consumed within the first few days, you would have sour flavored yogurt.

This isn't a how-to, rather some research notes. The conclusion at the moment is that making yogurt from milk at 4C would require a special yogurt bacterial strain that could outcompete other bacteria at 4C. The same way the normal yogurt strain can outcompete other bacteria at 43C.

Yogurt is stored in the fridge after it reaches maturity. Otherwise it goes sour. See: https://www.quora.com/How-did-one-store-yogurt-or-curd-before-the-invention-of-the-modern-refrigerator

So it would still be possible to drink yogurt that passed its optimal taste. But how do you know when not to drink it? “Whey typically runs clear, so if that water on top of your yogurt is looking a little cloudy, better play it safe and toss it out.” tastingtable.com

4 degrees celsius is the maximum temperature recommended for refrigerators. Would it be good to genetically engineer a yogurt culture that proliferates at 4C? This could extend the life of the milk as yogurt, with no heat and minimal effort. The idea is to add the culture right after opening the milk carton, or milking from the cow, and it would slowly become yoghurt. Raw milk would then still be healthy past 2-3 days.

The purpose of boiling is to kill unwanted microbes, but milk from a carton or straight from a healthy cow should be relatively free of microbes? According to the nourishedkitchen.com article above, raw milk has some naturally occurring non-harmful bacteria. In order to maintain a consistent taste, they will keep you using fresh starter culture for each batch of yogurt rather than reusing the resulting yogurt as a starter.

Regular yoghurt bacteria will not be active at 4 degrees Celsius.

Lactobacillus delbrueckii subsp. bulgaricus:

“ The optimum temperature and pH conditions for lactobacilli growth are 30–40 °C and 5.5–6.2, respectively; however, the Lactobacillus genus is diversified and belonging bacteria can grow in temperature ranging from 2 to 53 °C. ”. Growth Kinetics of Probiotic Lactobacillus Strains in the Alternative, Cost-Efficient Semi-Solid Fermentation Medium, Śliżewska and Chlebicz-Wójcik 2020

“ The optimum growth temperature for lactobacilli lies between 30 and 40°C but they can grow at temperatures ranging from as low as 5°C to an upper limit of 53°C, depending on the species. ”

Streptococcus thermophilus:

“ Because those organisms grow over different temperatures ranges, the term ‘cold’ can be used with respect to their behavior only in a relative sense, with reference to the minimum temperature for growth of each organism. Although a defining minimum temperature is often given for each group-40, 5, and <0°C for thermophiles, mesophiles, and psychrotrophs, respectively (3)-the minimum temperatures for growth of individual organisms within each group vary widely. ” Microbial Control with Cold Temperatures, Colin Gill 2001

From Wikipedia: “Yogurt made with raw milk can be contaminated with bacteria that can cause significant illness and death, including Listeria, Cryptosporidium, Campylobacter, Brucella, Escherichia coli and Salmonella.[41] Yogurts can also be contaminated with aflatoxin-producing Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius.”

Proliferation capacity of unwanted microbes at 0-4 Celsius:

Growth of Listeria monocytogenes at refrigeration temperatures, Walker et al 1990

Ingredients: fruit, thickener, stevia leaves.
Optional: citrus (lemon, etc), cloves, cinnamon, etc.

Cut fruit into chunks so the fruit juice can easily come out. For strawberries , slicing in half is sufficient. No need to remove the strawberry leaves as they are edible and healthy.

Put fruit into pot with stevia leaves and some tablespoons of water to cover bottom surface of pot. Apply medium heat and stir until it starts to look like lumpy soup. Do not overcook so fruit maintains its color. The goal is for some of the fruit juice to extract so it can mix with the thickener.

Lower heat to simmer and mix in thickener, like pectin or chuño. I only have experience with chuño. Keep stirring in additional thickener until fruit juice doesn't run on spoon. Turn off the heat. The fruit juice will thicken further upon cooling.

Before cooling, pour preserves into a sterilized glass jar until full. Seal with lid. Upon cooling, a proper lid will make an airtight seal.

The thickener, and optionally citric acid, will protect the preserves for at most a week after opening the sealed jar. The sealed jar will keep for close to a year, though I wouldn't know because I consume within 3 months.

I think even the healthier option oils are not healthy to consume. So an ideal diet would not have oil. Unfortunately, I live among families that are going to continue to use oil.

I have in memory that certain oils are healthier, such as first cold pressed olive oil with low acidity content. Also relatively healthy are coconut oil, avocado oil, almond oil, etc. These also happen to be relatively expensive.

I reserve this space to compilate research on healthier oil options, and where they fit in a diet, if at all.

Should You Refrigerate Your Cooking Oils? Cat Perry cleaneatingmag.com 2021

Influence of Heating during Cooking on Trans Fatty Acid Content of Edible Oils: A Systematic Review and Meta-Analysis, Bhat et al 2022