What Temperature Kills Yogurt Culture?

Simon King
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Temperature Settings

Yogurt is a dairy product made from milk through fermentation. It is, therefore, often used as a starter for baking other dairy products. It is often made using a yogurt machine or by fermentation in a water bath. The good news is that it does not require a starter culture.

In this post, we’ll look at temperature settings and time affects, which can increase or decrease the amount of lactose in the yogurt.

The good bacteria in the yogurt are the ones that convert the lactose to lactic acid. The amount of time they take to do that impacts the amount of acid and, therefore, the setting point of the yogurt.

The bacteria are most active when the temperature is warm, around 104 to 111. And they do not grow as much at 86 degrees, so that is why you would have to cook the milk to a higher temperature to get the yogurt.

As they are converting lactose into lactic acid, they release more than one byproduct, lactose and carbon dioxide. When the proteins are exposed to acid, they break up and aggregate. That is why you need to cook the milk until the aggregated proteins form a curd (curdling).

What Temperature Kills the Culture?

Fortunately for your tummy, even if a bacteria dies, it can still produce enough lactic acid to keep your yogurt safe.

So, technically, as long as you keep the bacteria from dying, you can produce good yogurt as long as you like. As long as the bacteria is alive, you can keep producing new batches of yogurt.

Hence, we have a hard time giving you an exact temperature with which to kill the bacteria.

However, because bacteria thrive at warm temperatures, it is recommended that you keep your culture at 130 degrees F and above.

Thus, you should be safe keeping it at about 140 degrees F.

Keep in mind that it's not the temperature itself that's the problem. It’s the length of time you keep it at that temperature. Most of the bacteria would be killed within ten minutes when kept at 140 degrees F. But since higher temperatures speed up the bacteria's activity, you should keep the yogurt at temperatures above 130 degrees F for a shorter period of time. Thus, 120 degrees should be okay if you only keep it there for a maximum of 10 minutes before moving it back to your warm home.

Maintaining Temperatures in Different Seasons

Yogurt is a healthy and delicious food that you can make at home. A few simple ingredients are mixed together to make a paste that is fermented over time.

Once this process is complete, you’ll have a tasty snack that has a unique bacterial culture that is great for your digestive system.

The fermentation process occurs in a few hours during the summer, but during the winter, it can be a lot longer. This is because yogurt cultures need a temperature difference to survive.

We know that the ideal temperature range for fermentation is between 70-84ºF. Temperatures below or above that range, have a much more negative effect. The yogurt cultures will die in temperatures below 45ºF, so make sure to keep it somewhere that is nice and warm.

And this is where it gets a bit tricky. It’s not that easy to control the room temperature that accurately. It depends on pretty much everything in the room.

The heating system, air flow, and even the walls will affect the overall temperature in the room.

A refrigerator is great to store yogurt cultures at the right temperature, but you won’t be able to monitor it every day.

So for your convenience, here is a rough guide for what temperatures will do the trick:

25ºF = ferment for about 10 days