There are two conditions you need in order to make yeast flourish in your dough: moisture and warmth. Moisture and humidity in the air can vary greatly from day to day and season to season. If your house is humid, your dough will rise faster.
Yeast can use oxygen to release the energy from sugar in a process called “respiration.” Thus, the more sugar there is, the more active the yeast will be and the faster its growth.
Yeast cells digest food to obtain energy for growth. Their favorite food is sugar in its various forms: sucrose (beet or cane sugar), fructose and glucose (found in white sugar, honey, molasses, maple syrup and fruit), and maltose (derived from starch in flour).
Like most other living organisms, they require three conditions for growth: moisture, food, and a hospitable environment. In such an environment, yeast will grow rapidly. Yeast feeds on sugar or converts the starch in the flour to sugar for food.
It requires moisture, warmth, food, and nutrients for their growth. These conditions help to fungi to grow and reproduce. Yeast is commercially cultured on an aerated suspension of molasses. It is a type of sugar that serves as a food source for the yeast.
It is reported that, most of the yeasts grow very well between pH 4.5-6.5, but nearly all species are able to grow in more acidic or alkaline media (17).
Yeast needs 3 things to thrive: moisture, food (sugar), and warm temperatures. When yeast is hydrated and given something to feed on it begins growing. Yeast's favorite food source is sugar in its various forms. Yeast doesn't just feed on white sugar, but it can feed on carbohydrates in any form.
Fermentation times can be shortened by using powdery (non-flocculent) strains of yeast or by mechanically stirring the fermenting wort. The yeast can also be roused toward the end of fermentation by the injection of carbon dioxide or by using a re-circulating device.
In order for fermentation to take place, all yeast needs food, moisture and a controlled warm environment. Its byproducts from consuming food are the gas carbon dioxide, alcohol, and other organic compounds.
Water: For best results, use water that is heated to 110 – 115 degrees Fahrenheit and use a thermometer. Any temperature between 75 degrees and 130 degrees should work, but yeast dies at 138 degrees. Some recipes use milk instead of water to activate yeast, so just follow your recipe.
The increase in sugar concentration causes declines in yeast cell growth and size.
While sugar and other sweeteners provide "food" for yeast, too much sugar can damage yeast, drawing liquid from the yeast and hampering its growth. Too much sugar also slows down gluten development. Add extra yeast to the recipe or find a similar recipe with less sugar. Sweet yeast doughs will take longer to rise.
Sugar is nutrition for yeast, it consumes it and produces CO2. Yeasts produces enzymes that react with sugar. The yeasts, like most fungi, respires oxygen (aerobic respiration), but in the absence of air they derive energy by fermenting sugars and carbohydrates to produce ethanol and carbon dioxide.
To activate yeast, you need water and a touch of granulated sugar. Follow these steps to activate yeast: Adjust your tap water until it feels lukewarm. The ideal water temperature to proof yeast is 100–110 degrees Fahrenheit.
Nitrogen, the most important yeast nutrient, is a key factor that has a significant impact on wine fermentation. Why do yeasts need nutrients? Nitrogen (YAN), vitamins (thiamine) and mineral salts (Mg, Zn) are essential for yeast activity.
It has been estimated that a 1°C rise in dough temperature will accelerate yeast activity by about 10 percent. Correspondingly a decrease will cause a similar slowdown of yeast activity. As dough ferments, heat is generated, raising the dough temperature and accelerating the yeast activity.
Yeast feeds on sugar so by adding a tablespoon or two provides yeast a readily available food. This increases yeast's activity and speeds up fermentation as well. However, adding a large amount of sugar to your dough will affect yeast's metabolism. Sugar is hygroscopic which means it absorbs moisture from the dough.
To Speed Up The Ferment
By adding a bit of vinegar to a ferment, it creates an environment that is ideal for acid-loving bacteria, thus speeding up the fermentation time.
80° F—90° F (27° C–32° C) Optimum temperature range for yeast to grow and reproduce at dough fermentation stage.
cerevisiae and other yeast species eat sugar and produce byproducts including carbon dioxide (responsible for the air pockets in leavened bread) and alcohol (think wine and beer). “Yeast evolved to take advantage of high-sugar plant material that came about when flowering plants emerged,” she says.
Salt acts as a yeast inhibitor, which means that it slows down the growth and reproduction of yeast in your bread dough.
Too much flour in the dough – if it's too dry and heavy, the yeast can't lift it! Not enough kneading – the gluten didn't develop enough to let the yeast lift it. Salt was added to yeast directly or too much salt was added — this can kill the yeast! Try to add salt last, mixed in with the flour.
Yeast, for example, lives 40% longer when grown at the elevated – and mildly stressful – temperature of 37°C instead of 30°C.
Answer and Explanation: Yeast needs sugar and oxygen to grow. Yeast also needs the right temperature to grow. Air that is at room temperature or water that is slightly warm is needed to activate yeast.