As an expert sommelier and brewer, I have had plenty of experience working with yeast in various forms. When it comes to dissolved yeast in water, there are a few key characteristics to look out for.
Firstly, it is important to ensure that your water is at the correct temperature. Yeast is a living organism, and it thrives in a certain temperature range. If your water is too hot, it can kill the yeast, resulting in a failed fermentation process. On the other hand, if your water is too cold, it can inhibit yeast activity. Ideally, you want your water to be warm, around 100-110°F (38-43°C), to activate the yeast.
Once you have added the yeast to the water, it's time to observe its reaction. If your yeast is fresh and active, you should start to see some bubbles forming on the surface of the mixture within a few minutes. These bubbles are a result of the yeast consuming the sugars present in the water and producing carbon dioxide gas as a byproduct.
In addition to the bubbles, you may also notice a slight foamy layer forming on top of the yeast mixture. This foam is another indication that the yeast is active and working to ferment the sugars. It is a sign that the yeast cells are multiplying and producing carbon dioxide.
However, if your yeast mixture looks cloudy and flat instead of foamy and bubbly, it could be a sign of a problem. There are a few possible reasons for this outcome. Firstly, if your water was too hot when you added the yeast, it could have killed off the yeast cells, preventing fermentation from occurring. It's crucial to ensure that your water is within the appropriate temperature range to avoid this issue.
Another possibility is that your yeast may be old or expired. Yeast is a living organism, and over time, it can lose its viability. If you're using yeast that has been sitting in your pantry for a while, it may not be as active as it should be. In this case, it's best to start over with fresh yeast to ensure a successful fermentation.
To summarize, dissolved yeast in water should appear bubbly and foamy if it is fresh and active. The bubbles and foam are indications that the yeast is consuming the sugars and producing carbon dioxide. If the yeast mixture looks cloudy and flat, it could be due to water that was too hot or yeast that is past its prime. Taking care with the temperature of your water and using fresh yeast will help ensure a successful fermentation process.