Sunday, July 22, 2018

Yogurt from store-bought starter

Each spring and summer our homestead produces a bounty of fresh goat's milk from our small backyard herd of Saanen cross goats. While we make many things with the milk - from custard to soft cheese chèvre and even goat's milk soap - my family's favorite is yogurt. There are many methods of making yogurt, often using specialty cultures bought from cheesemaking supplies and specialized yogurt incubators. To avoid having to buy & ship cultures and owning another piece of equipment, I found a fool-proof way of making yogurt with off-the-shelf yogurt and my oven. We now enjoy fresh yogurt whenever we like!

My doe Gazelle with her Saanen x Nubian twins.

Yogurt is a fermented milk product that provides digested lactose and specific viable bacterial strains, typically Streptococcus thermophilus and Lactobacillus bulgaricus. It is a source of several essential nutrients, including protein, calcium, potassium and vitamins B2 and B12. With the domestication of milk-producing animals like cows, sheep and goats, as well as horses, buffalo and yaks, milk products became a part of the human diet. It is generally thought yogurt, and other fermented milk products, were discovered by accident as a result of milk being stored by primitive methods in warm climates. Milk spoils easily, making it difficult to use. Herdsmen in the Middle East discovered that milk carried around in bags make from intestinal gut would cause the milk to curdle and sour - the rennet from the intestinal juices would preserve and help conserve the otherwise easy to spoil milk for extended periods of time. For millennia, making yogurt was the only known safe method for preserving milk, other than drying it in the form of cheese. The Greeks were the first to write about yogurt at around 100BC, mentioning the use of it by barbarous nations. Genghis Khan reputedly fed his army yogurt - already a staple of the Mongolian diet - because he thought it instilled bravery in his warriors! It is generally thought the word 'yogurt' comes from the Turkish word 'yoğurmak,' which means to thicken or curdle.

The first industrialized production of yogurt started in 1919 in Barcelona by Isaac Carasso – he named the company 'Danone,' or 'Little Daniel,' for his son. While Turkish immigrants had brought yogurt to North America in the 1700s, it did not really catch on until the 1940s. That is when Daniel Carasso, the son of Danone founder Isaac, and Juan Metzger took over a small yogurt factory in the Bronx, New York, renamed it Dannon and quickly introduced yogurt with fruit on the bottom in 1947. The popularity of yogurt soared in the 50s and 60s with the boom of the health food culture and is now readily available in many varieties, including sheep and goat's milk yogurt. The types of yogurt typically available today are influenced by local traditions and lifestyles. For instance, Eastern European and Asian cultures have the milk undergo an alcoholic fermentation to make kefir and koumis. In Spain and Germany, yogurt is typically heat-treated to kill the bacteria, and in the United States as well as other countries, various probiotics and/or prebiotics are added to the mix.

It has been my experience that certain off-the-shelf yogurts work much different than others - they all make yogurt but some of the textures were not what I would call pleasing. From all the different yogurt brands I’ve played with, Stonyfield Organic is the most consistent. It is important to make sure the jars are sterile to avoid contamination with unwanted bacteria and yeasts, and to start with a healthy starter to promote vigorous fermentation of the right cultures. Especially households that make other ferments like vinegar, bread and kefir do well to pay close attention to cleanliness. But once you've got your ducks in a row, the actual process of making yogurt is pretty simple and takes less effort than you might expect!

Yogurt starter, milk and heat – all the essentials for wholesome homemade yogurt!

What you'll need:
- one gallon organic whole milk (I use raw backyard goat milk)
- 1 to 2 cups of Stonyfield Organic Yogurt (I use low fat as I am cow dairy sensitive)
- stainless steel pot or a Dutch oven
- thermometer
- stainless steel wisk
- wide mouth (canning) funnel
- five mason jars with lids
 
How to sterilize?
There are several methods of sterilizing equipment: anyone who has canned before should be all set. Anything that is in contact with the milk after it is pasteurized should be sterilized; this includes the funnel, the mason jars and the lids.

As I brew as well, I sterilized my mason jars using the brewing sanitizer Star-San and stored the jars on my dishwasher drawer - this is quick and energy efficient.

Method one: run the jars and lids through the hot / canning setting of your dishwasher.
Method two: boil the jars and lids in your water-bath canner for 10 minutes (just like prepping jars for canning).
Method three: use a brewing sanitizer like Star-San, or iodine.
Method four: soak in a sterilizing bleach bath, and rinse very well afterwards.

Step by Step on making yogurt:
- Heat your milk to 182°F (this pasteurizes the milk).


- Let it sit for 10 minutes on low at around 182°F.


- Fill your sink with cold water (add some ice packs if you have them). Put the pan with hot milk in the cold water to cool the milk down to 110-120°F.
- Scoop 2 cups of Stonyfield yogurt into the lukewarm milk. If the yogurt is straight from the fridge, add at 120°F; if it is room temperature, add at around 110-115°F. You want the cultured milk to be at around 110°F.


- Gently whisk the yogurt culture into the milk. If you like, you can dilute it separately in some of your milk so it is less chunky and dissolves easier but this is not necessary.
- Pour the cultured milk into mason jars (use wide mouth funnel) and close the lid.


- Put the mason jars with cultured milk into the oven – leave the pilot or the general light on.


- Leave overnight, the next morning your yogurt is ready for consumption (after that, refrigerate).

Some beautiful fermentation is visible at the rim of the fresh yogurt.

The trick to culturing yogurt is to use a (turned off) kitchen oven as an incubator – it is well insulated and every house has one. If you have an old-fashioned gas stove which lights with a pilot light, that is all it needs to stay all nice and cozy inside. If your oven does not have a pilot light, it should have a regular light bulb to see what is going on inside. Leave that on (with the door closed), and it will keep the oven just as comfortable – a perfect environment for culturing yogurt.

Tip: if you strain your yogurt through some cheesecloth until it is as thick as you like, you just made your very own thicker Greek-style yogurt.

Reference:

DIY medieval hard white soap.


Castile soap – a well-known olive oil soap with a long-time history, it is named for the city it reportedly originated. Originally made from unfiltered olive oil and lye produced from burning the plant barilla, castile soap still has an all-natural reputation and is perfect for vegetarians and vegans as it is made of vegetable oils only. While in Spain castile soap means soap made in the Castilla area from 100% olive oil, in modern times the term ‘castile’ can have other meanings. Commercially available Castile soaps are often a blend of olive oil with coconut and palm oils, and here castile indicates the bulk of the oils comes from olives. The term castile is also used to indicate vegetable oils-only soaps, and even slightly viscous liquid soap made only with vegetable oil.

Aleppo soap 03.jpg
Aleppo soap at the Al-Jebeili factory, Aleppo, Syria (Creative Commons)

Most people are familiar with the solid bar olive oil soap and some might even know its Spanish roots. But did you know that another soap made from only olive oil, called simply ‘white soap,’ originated in Northern Italy hundreds of years before castile soap appeared in Spain? And the European claim is not even as old as the even older more fabled source – Aleppo soap, made of olive and laurel berry oils. This hard soap originated in the city of Aleppo and goes back at least a thousand years; as well as its cousin Nabulsi soap, made in Nablus, Palestine. It is generally thought that the invading ‘Moors’ of North Africa brought the technology of making hard white soap with them to medieval Southern Europe. With the prevalence of the plant barilla in Southern Europe - an essential ingredient in the making of hard soap - the craft of hard soap making was quickly picked up by the Europeans and evolved into lucrative local soap making centers, like in Castilla, Spain and in Marseilles, France.

Why go through the trouble of making your own soap?
Not all soaps are made alike and unless you know what went in it many olive oil soaps might not be as healthy as you would wish. There are different grades of olive oil, depending on how it is processed. They all work for making soap, though I would advice to stay away from pomace olive oil. While this is cheapest, there is a reason! Pomace means that it is made of the solid remains of the olive including skins, pulp, seeds, and stems, and the amount of oil left is so minimal that it cannot be extracted by pressing, but only through the combined use of chemical solvents and extremely high heat. Cheap filler oils like canola and palm oil are also often included in modern castile soaps. In the case of palm oil: unless it is certified organic and sustainably farmed, I do not use it as standard production attributes to rainforest deforestation. Olive oil-only soaps are readily available from artisanal soap makers but sometimes it’s easier – and a lot more fun – to just go ahead and make your own!

Why make soap in a soda bottle?
The exothermic or heat creating reaction of dissolving lye crystals into water heats the water to (near) boiling and creates a lot of very dangerous caustic steam. Experienced soap makers learn how to work around this, either by making lye outdoors (and being upwind ourselves), by using (partially) frozen liquid, or by using ventilation. The soda bottle method keeps the steam contained as we wait for it to cool down and condense again. Steam, as it is a water vapor, or gas, takes up more room than liquid water, and in a confined area like a bottle will build up pressure. Soda bottles are designed to take this pressure, as long as there is enough space left in the bottle to do so. Using this technique anyone can make small amounts of hard soap without the need for specialized equipment. But do always keep your wits about, as lye will always be a potentially dangerous chemical.

 
Measuring out the lye, the soap bottle and the water are at the ready.
 
Measured the oil.
Needed:
- 2 liter soda pop bottle, with lid.
- 5 gallon bucket
- Lye
- Water
- Ice cubes
- Olive oil
- Funnels (one for water, one for lye)
- Rubber spatula
- Scale, preferably digital.
- Paper Towels
- Household vinegar
- Rubber gloves
- Safety glasses

About the bottle:
PET (polyethylene terephthalate) bottles are not specifically made for extreme temperatures; they are made to withstand pressure very well, and are easy to get as 2 liter soda pop bottles. PET plastic should not contain BPA but might contain traces due to the (recycled) manufacturing process. BPA is not food safe but only releases slowly from contaminated plastic under high temperatures, and while the lye creates high temperatures, it does so only for a short while.  To minimize heat, a bucket with ice water should be at the ready before mixing the lye water.

Do NOT OVERFILL the bottle. Stick to the recommended minimal amount of oil and lye. The empty space in the bottle is needed as a pressure chamber for heat expansion. The exothermic (heat creating) reaction of dissolving lye in water, heats the water to boiling and creates lots of steam. This steam is highly caustic and VERY dangerous, hence the closed-off bottle pressure chamber.

About the lye:
Up until recently, lye would be available in the household cleaning isle of the supermarket and hardware store. Alas, as it is used to make certain other stuff, this is no more. Do not buy liquid lye to make soap, as it is not possible to measure the amount of dissolved lye correctly, plus, there are additives added you do not want in your soap. Food grade lye can be bought over the internet and I get mine from here: http://essentialdepot.com/

About Safety:
When working with sodium hydroxide lye ALWAYS wear SAFETY GLASSES. It is recommended to wear gloves, and always have household vinegar nearby for the unexpected splash or droplet. Wear closed shoes and long sleeves if possible.

For a nice amount of hard soap for personal use a 10 ounce olive oil batch works well.

Step by step:

  • Measure 10 weight ounces of (room temperature) olive oil.
  • Measure 1.26 ounces of lye.
  • Measure 2 ounces of cold water.

- Fill a 5 gallon bucket with a water and ice mixture.
- Add water to soda bottle with funnel.
- Slowly but steadily add lye crystals to water in bottle with the other dry funnel.
- When done, close lid immediately, and shake gently.
- Stick into ice-water right away when all the lye is dissolved.
- The bottle will start to fill with steam, get scorching hot and swell. Do not touch at the bottom! It should already be in the ice-water.
- After about 5-10 minutes check bottle.
- If the bottle’s bottom shrank, it could benefit from ice-water a little quicker next time.
- The steam should be condensing on the sides and run down in droplets.

 Water droplets condensing on the sides.

A slightly overheated shrunken soap bottle bottom.

- When the bottom of the bottle, with the liquid, feels not cold nor warm (body temperature, also called blood warm) it is time.
- Open bottle cap, and add oil to blood warm lye.

Oil sitting on top of lye water.

      All mixed up by shaking.

- And now it’s time to shake your booty! Do put the cap back on first.
- Shake, shake, and shake some more…
- When the soap starts to stick and coat the sides of the bottle like custard, it is good.

Raw soap at the ‘custard’ stage.

If you like, this is the moment you can pour the soap into a mold, or into a small water bottle to make soap rounds (for instance to make felted soap). Remove the top of the bottle first, and use a rubber spatula to get it all out.


If you do not intend to mold, remove the lid, set it somewhere safe and let it sit open until the sides of the soap are totally firm. Cut off the top of the bottle, and pop out your block of soap!

Cut your soap to size in a week or so (do not wait too long, olive soap is notorious for getting crumbly) Let the pieces dry on a cookie drying rack in a cool and dark place for a minimum of three weeks.

Tip: you can let the soap dry completely in the bottle, but make sure to remove the lid. If dried in a (partially) closed environment the soap can ‘sweat’ a little – this will either go away on its own, or you can dab it dry later with a paper towel.

As with all hand made soap, when in use place the soap on a draining soap dish to let dry in between uses and it will go a long way - a green Scotchbrite pad cut in half makes a fabulous cheap soap dish. As has been said: the longer it sits, the harder it gets, and the longer it stays!


References:
Dunn, Kevin. Caveman Chemistry. Universal Publishers, 2003.
Dunn, Kevin. Scientific Soapmaking. Farmville, VA: Clavicula Press, 2010 (p.58)

About the safety of using plastic bottles:

About castile soap in general:

Creative Commons image;