Maintaining Temperatures for Culturing Yogurt

One of the most important things to consider when you are making yogurt is the temperature at which it cultures.

Thermophilic Yogurt Cultures

Thermophilic yogurt cultures require a temperature in the range of 110°F to reproduce properly. Anywhere in a range of 105°F to 112°F will be adequate, but under 105°F or over 112°F can weaken or damage the bacteria, and will cause the milk to not set up at all, or to curdle without culturing. Temperatures over 118°F will kill the culture, and just heat the milk without culturing it or providing any probiotic benefit.

There are a variety of yogurt makers on the market that are designed specifically to keep milk at a constant temperature of around 110°F. They come with plastic or glass inserts that will hold the milk+culture, and either a timer that will turn off the machine at the end of the culturing time, or a “reminder” dial that you can set to remind you to turn off the machine itself.

To verify that a yogurt maker is running at the right temperature, fill the container(s) with water that has been heated to 110°F, turn on the machine, and check the temperature of the water every half hour. It should be fairly constant, and within the range of 105° to 112°F. This is the correct temperature for culturing any brand of thermophilic yogurt and any type of milk.

If you don’t have a yogurt maker, there are many ways you can maintain the proper temperature for culturing. In each case you can verify the culturing temperature by heating some water to 110°F, putting it in a jar such as you would use for making yogurt, then checking the temperature of the water at the end of what would be the normal culturing time.

Food Dehydrator. A cabinet-style food dehydrator, with the shelves removed, makes a perfect warm box for culturing yogurt. The dehydrator must have a setting low enough for the yogurt, as most do. The door of the dehydrator can be left open or closed, to get just the right temperature for the yogurt.

Insulated Container. You can make an insulated yogurt incubator with a small crockpot and some 1-inch foam. Cut two circles of foam to fit the bottom of the crockpot. Then cut another strip of foam about two inches narrow than the inside height of the crockpot, and as long as the inside circumference of the pot. Put one circle on the bottom of the pot, and wrap the long strip around the inside of the pot. Put the yogurt inside the foam-lined pot, put a lid on it, put the other circle on top of it, and put the crockpot lid on top of that. You can use any sort of enclosed container with foam to make a good insulated yogurt incubator.

Warm Oven. If you turn the light on inside your oven and close the door, the inside of the oven may stay at around 105° to 110°F. You will have to test this though, as some ovens run considerably cooler, and some run warmer. If your oven maintains the right temperature with just the light on, wrap your jar of yogurt in a clean dishtowel secured by a rubber band, and set it on a cookie sheet or in a shallow pan in the oven with the light on. Or, if you have a gas oven, the pilot light alone may keep the oven at a constant culturing temperature. (Again, you should test it first.)

Appliance Boost. Many people have appliances in their homes such as DVRs that are “always on”. You can wrap your covered jar of yogurt in a clean dishtowel secured by a rubber band, and set it on top of the appliance to culture. With electronic equipment, it is strongly advised that you put the yogurt in or on a dish or pan to protect against accidental spills.

Seedling Mat. Nurseries and greenhouses often sell seedling mats (or can tell you where to buy one), which are small flat heating pads that can be set to produce heat from around 68° to around 108°F. This is a little on the cool side for a thermophilic yogurt, but if your environment is quite cold, it could be a good option.

Open Insulation. If your house is warm enough, or if you have a counter that is in a warm place in your kitchen, it may be sufficient to simply wrap your covered jar of yogurt in a clean dishtowel secured by a rubber band, and set it in that warm place. 

Hot Water Bath. In a pinch, you can use a hot water bath to keep your yogurt warm enough to culture. Set the covered yogurt jar in a larger bowl, and fill the bowl with heated water, to anywhere from an inch or two up from the bottom of the jar, to an inch or two from the top of the jar. You can use a thermometer to measure the temperature of the water. 110°F is like a very hot bath – but still cool enough to put your finger in easily. As the water cools, you can pour it out and replace it with more. (Lift the yogurt out very gently, being careful not to disturb it, then pour the water out of the larger bowl and replace the yogurt, then the heated water.) This is pretty labor- and time-intensive, and really only useful as an emergency measure when there are no other options.

Mesophilic Cultures

Yogurt cultures that work at room temperature must also work within a certain range. Below 68°F, a mesophilic culture will go dormant, and may cease to reproduce. When a mesophilic culture stops working after having been activated, it is unlikely to start working again, although the bacteria are still viable, and any probiotic benefit that is already in the yogurt will still be there.

Mesophilic bacteria will be killed at 85°F, and will not have any probiotic benefit, nor will they reproduce. These yogurts work best between 70° and 80°F, with the ideal temperature being around 75°F.

It is a little easier to keep a mesophilic yogurt within culturing range, but summer temperatures can be too warm, causing overculturing and curdling, and winter or nighttime temperatures can be too cool, causing the culture to halt.

Yogurt makers, dehydrators, and ovens are generally too warm for mesophilic cultures. Some of the other methods for warming thermophilic yogurts can also be used for mesophilic varieties.

Keeping it Warm

Appliance Boost. Many people have appliances in their homes such as DVRs that are “always on”. Wrapping a dishtowel around the yogurt may make it too warm, but you can simply set the jar on top of the appliance to culture. With electronic equipment, it is strongly advised that you put the yogurt in or on a dish or pan to protect against accidental spills. 

Seedling or Reptile Mat. A seedling mat from a nursery or greenhouse or a reptile mat from a pet store can be set to around 75°F which is perfect for a mesophilic yogurt.

Elevation. It may be sufficient to simply set your yogurt in a high place in your kitchen, where the air is a little warmer than at counter height.

Hot Water Bath. In a pinch, you can use a hot water bath to keep your yogurt warm enough to culture. Set the covered yogurt jar in a larger bowl, and fill the bowl with heated water, to anywhere from an inch or two up from the bottom of the jar, to an inch or two from the top of the jar. You can use a thermometer to measure the temperature of the water. 75°F will feel lukewarm. As the water cools, you can pour it out and replace it with more. (Lift the yogurt out very gently, being careful not to disturb it, then pour the water out of the larger bowl and replace the yogurt, then the heated water.) This is pretty labor- and time-intensive, and really only useful as an emergency measure when there are no other options.

Culturing Box. You may be able to maintain a “room temperature” environment by just putting your yogurt inside a food cooler along with a jar of hot water. Check the cooler occasionally and replace the hot water if necessary to maintain a temperature inside the cooler of at least 70°F.

Warm Oven. If you turn the light on inside your oven and close the door, the inside of the oven may stay at around 80°F. You will have to test this though, as some ovens run cooler, and some run warmer. If your oven maintains the right temperature with just the light on, wrap your jar of yogurt in a clean dishtowel secured by a rubber band, and set it on a cookie sheet or in a shallow pan in the oven with the light on. Or, if you have a gas oven, the pilot light alone may keep the oven at a constant culturing temperature. (Again, you should test it first.)

Keeping it Cool

In the summer, it can be a challenge to keep yogurt cool enough to culture! There are a few tricks that can help you here too.

Culturing Box. Just as you can use a food cooler to keep yogurt warm in winter, you can use it to create a cool environment as well. In very hot weather, a cooler with an icepack inside will usually provide just the right temperature for mesophilic yogurt to culture successfully. Experiment with this to find the right size icepack and cooler combination.

Cooling Surface. Marble tends to stay cooler than the surrounding environment. If you have marble countertops, or a marble slab, you can place the yogurt there and it will keep the culturing temperature down.

Evaporational Cooling. Place the jar of yogurt in shallow bowl of cool water. (A pie plate or cake pan can work.) As the water in the bowl evaporates, it provides a cooling effect. You don’t need to change out the water, as it will stay fairly cool, but replace it if it evaporates away. The water should be tepid, not cold.

 


 

 

 

 

                                                
   
Homemade Yogurt and Fruit Plate


Related Articles & Recipes:

 

Related Products:

Bulgarian Yogurt Starter Yogurt Starter
Yogurt Maker Yogurt Makers
Cotton Bag for Making Yogurt Cheese Lebneh
Cotton Bag for Making Soft Cheese

 

<table style="width: 506px;" border="0" align="left">
<tbody>
<tr>
<td><span style="font-family: verdana,geneva; font-size: small;">&nbsp;</span> <br />
<p><span style="font-family: verdana,geneva; font-size: small;">Originally a simple fermented dairy product, yogurt now has many variations and personalities. It can be thin and runny, or thick and firm. It can be made from cow milk, goat milk, sheep milk, nut milk, soy milk, rice milk, and from numerous other creamy substances. In some countries the milk of buffalo, horses, yaks, or camels is used.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">For most of this discussion, we&rsquo;ll refer to yogurt in its original form: a fermented dairy milk. This was how yogurt was first developed, and most of the yogurt in the world is made this way.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">Essentially yogurt is the product of beneficial bacteria fermenting milk and turning it into a thickened, acidic food that will stay fresh longer than milk itself, and that contains millions of bacteria that are welcomed by the human gut.</span></p>
<h1><br /><strong><span style="font-family: verdana,geneva; font-size: small;">The History of Yogurt</span></strong></h1>
<p><span style="font-family: verdana,geneva; font-size: small;">The word yogurt comes from a Turkish word meaning to curdle or to thicken. Today it is spelled yogurt, yoghurt, or yogourt, with yogurt being the most common American spelling.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">It&rsquo;s probable that the earliest yogurt was made by accident in Mesopotamia around 5,000 BC, when milk-producing animals were first domesticated. The milk was likely stored and transported in bags made from the stomachs of these animals, and the digestive juices and bacteria in the stomach linings made the milk coagulate and become acidic. Not only was it a new and interesting food, but the acidity and helped to keep it edible for longer</span> <span style="font-family: verdana,geneva; font-size: small;">than if it had just sat out in a bowl or jar.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">There is also some evidence of yogurt being used as a cleaning product and a beauty lotion as early as 2000 BC. The acidity of the yogurt helps clean away dirt and rust, and also helps clear away dead skin and nourish healthy skin cells.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">Yogurt was a popular food in the Middle East for thousands of years, and has been a staple of the Eastern European diet. It&rsquo;s now eaten throughout the world, as a main course, a snack, an ingredient in many recipes, and a condiment. It has gained considerable popularity in America in the last forty or fifty years, in keeping with general trends toward organic, cultured, and nutrient-dense foods.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">Yogurt can be mildly tart or quite sour, and can be thick enough to stand up on a plate, or thin enough to pour, or anywhere in between. It contains protein and calcium as well as a variety of vitamins. Additionally, the process of yogurt fermentation is very similar to the process of digestion, so it can be easily consumed.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">Many people eat yogurt plain, while others prefer to mix it with fruits or vegetables, or to add flavors or sweeteners. It is used in a variety of recipes as a flavor enhancer or leavening, and frequently enjoyed as a refreshing drink.</span></p>
<h1><br /><strong><span style="font-family: verdana,geneva; font-size: small;">Nutritional Content</span></strong></h1>
<p><span style="font-family: verdana,geneva; font-size: small;">Not only does yogurt contain the same amount of protein and fat as the milk from which it is made, it also contains calcium, riboflavin, vitamin B6, and vitamin B12. While numerous claims have been made regarding the health benefits and digestibility of yogurt, we don&rsquo;t comment on medical, health, or nutritional qualities of our products. However, a great deal of research on the subject is readily available on the Internet and in dozens of books.</span></p>
<h1><br /><strong><span style="font-family: verdana,geneva; font-size: small;">How is Yogurt Made?</span></strong></h1>
<p><strong><span style="font-family: verdana,geneva; font-size: small;">&nbsp;</span></strong><span style="font-family: verdana,geneva; font-size: small;">True yogurt is made from animal milk. Theoretically, the milk of any mammal could be used to make yogurt.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">With care, yogurt cultures can also be used to ferment and coagulate non-dairy &ldquo;milks&rdquo; such as the creamy liquid obtained from nuts, rice, soy, or coconut. While these products are technically not really yogurt, they can be used and enjoyed just like dairy yogurt, alone or in recipes.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">Put very simply, the process of turning milk into yogurt involves fermentation. Certain types of bacteria act on the lactose (milk sugar) that is in milk, and produce lactic acid. The lactic acid lowers the pH of the milk, and causes the milk protein to coagulate and make a firm mass. The acidified milk is an inhospitable environment for destructive bacteria, so the yogurt stays fresh longer than untreated milk.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">The bacteria that does this is called beneficial bacteria, because it supports digestion and is nourishing, as opposed to pathogenic (harmful) bacteria that causes disease. The beneficial bacteria is called probiotic. It&nbsp; is similar or identical to the type of bacteria that lives in the human gut and which is responsible for the process of food absorption. When you use live cultures, the probiotics stay in the yogurt, and the yogurt can then be used as a starter to make more yogurt.</span></p>
<h1><br /><strong><span style="font-family: verdana,geneva; font-size: small;">Yogurt and Other Fermented Dairy Products</span></strong></h1>
<p><span style="font-family: verdana,geneva; font-size: small;">There are many different ways that beneficial bacteria can be introduced to milk and make an entirely new food. The main difference between the different fermented dairy products is the bacteria used to make them, resulting in different flavors and consistencies.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Yogurt</em> can be cultured with a variety of different bacteria combinations, each of which gives the yogurt a characteristic taste and consistency. There are typically somewhere between the range of two to six different bacteria strains in yogurt, and they are similar to the bacteria found in the intestines.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Kefir</em> is a thickened milk made from little clumps of yeast, bacteria, and milk proteins that ferment the milk. There are about thirty different bacteria strains present in kefir grains. It has a slightly sour flavor and sometimes a faint effervescence. Koumiss is a similar product, made from mare&rsquo;s milk.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Buttermilk</em> is the name given to the whey that&rsquo;s left over when butter is made, but it more commonly refers to a milk drink made by adding bacteria to low-fat milk, producing a thickened product with a tangy flavor.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Sour cream</em> is cream or high-fat milk that&rsquo;s been cultured and thickened. It&rsquo;s very slightly sour, and usually quite thick. It was originally made by letting fresh cream thicken naturally as a result of fermentation from the bacteria present in the cream. When cream is pasteurized and has no natural bacteria present, it must be fermented with added bacteria.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Cr&egrave;me fraiche</em> is a European-style sour cream, slightly sweeter than what we are used to in America. It&rsquo;s also made by letting raw cream thicken naturally, or by adding buttermilk cultures to cream. Cr&egrave;me fraiche can be heated without curdling, unlike sour cream.</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;">In recipes, you can often substitute one cultured milk product for another and get similar results. In fact, sometimes it is hard to tell the difference between a thin, tart yogurt and a thick, sour kefir or a creamy buttermilk!</span><br /><br /><span style="font-family: verdana,geneva; font-size: small;"><em>Soft and hard cheeses</em> are also made by culturing milk over a longer period of time. Some cheeses can be easily made by straining the moisture out of yogurt or sour cream, while others require additional fermentation and culturing steps.</span></p>
<ul>
</ul>
<ul>
</ul>
<ul>
</ul>
<ol> </ol>
<p><br /><br /></p>
</td>
<td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; <br /></td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
</tr>
</tbody>
</table>
<table style="width: 200px;" border="0" align="left">
<tbody>
<tr>
<td colspan="2"><img src="http://cdn.culturesforhealth.com/media//Greek_Yogurt_200px_1.jpg" alt="Yogurt" /><br /></td>
</tr>
<tr>
<td colspan="2">
<p><span style="font-family: verdana,geneva;"><br /><strong>Related Articles &amp; Recipes:</strong></span></p>
<ul>
<li><a title="Yogurt Making How-to Videos" href="http://www.culturesforhealth.com/how-to-videos#yogurt_video" target="_blank"><span style="font-family: verdana,geneva; font-size: small;">Yogurt Making How-to Videos</span></a></li>
<li><a title="How to Make Lebneh" href="http://www.culturesforhealth.com/how-to-make-lebneh-yogurt-cheese" target="_blank"><span style="font-family: verdana,geneva; font-size: small;">How to Make Lebneh (aka Yogurt Cheese)</span></a><span style="font-family: verdana,geneva;">&nbsp;</span></li>
<li><span style="font-family: verdana,geneva;"><a title="Yogurt FAQ" href="http://www.culturesforhealth.com/expert-advice/Yogurt-Starter-FAQ.html" target="_blank">Yogurt FAQ</a><br /></span></li>
</ul>
<p>&nbsp;</p>
</td>
</tr>
<tr>
<td colspan="2">
<p><strong><span style="font-family: verdana,geneva;">Related Products:</span></strong></p>
</td>
</tr>
<tr>
<td><a title="Yogurt Starter" href="http://www.culturesforhealth.com/starter-cultures/yogurt-starter.html" target="_blank"><img src="http://cdn.culturesforhealth.com/media//Bulgarian_75px.jpg" alt="Bulgarian Yogurt Starter" /></a></td>
<td><a title="Yogurt Starter" href="http://www.culturesforhealth.com/starter-cultures/yogurt-starter.html" target="_blank"><span style="font-family: verdana,geneva;">Yogurt Starter</span></a></td>
</tr>
<tr>
<td><a title="Yogurt Makers" href="http://www.culturesforhealth.com/kitchen-appliances-1/yogurt-makers.html" target="_blank"><img src="http://cdn.culturesforhealth.com/media//Euro_Cuisine_Yogurt_Maker_YM80_75px.jpg" alt="Yogurt Maker" /></a></td>
<td><a title="Yogurt Starter" href="http://www.culturesforhealth.com/starter-cultures/yogurt-starter.html" target="_blank"><span style="font-family: verdana,geneva;"></span></a><a title="Yogurt Makers" href="http://www.culturesforhealth.com/kitchen-appliances-1/yogurt-makers.html" target="_blank"><span style="font-family: verdana,geneva; font-size: small;">Yogurt Makers</span></a></td>
</tr>
<tr>
<td><a title="Cotton Bag for Making Soft Cheese" href="http://www.culturesforhealth.com/cotton-bag-for-making-soft-cheese.html" target="_blank"><img src="http://cdn.culturesforhealth.com/media//Soft_Cheese_Bag_75px.jpg" alt="Cotton Bag for Making Yogurt Cheese Lebneh" /></a><br /></td>
<td><a title="Cotton Bag for Making Soft Cheese" href="http://www.culturesforhealth.com/cotton-bag-for-making-soft-cheese.html" target="_blank"><span style="font-family: verdana,geneva;">Cotton Bag for Making Soft Cheese</span></a></td>
</tr>
</tbody>
</table>

Free eBook Library Access & Weekly Newsletter


Sign up today for free access to our entire library of easy to follow eBooks on creating cultured foods at home, including Lacto-Fermentation, Kombucha, Kefir, Yogurt, Sourdough, and Cheesemaking.
  • Library of eBooks for making your own cultured foods
  • Weekly newsletter filled with tips & tricks
  • Expert advice articles, recipes, and how-to videos
  • Join 140,000+ other health-conscious readers
  • We never share your information!
first name last name email address