Whether you decide to ferment off the grain or on the grain, the entire process of fermentation will remain the same for both so you have to keep a keen eye on this process because it is really important in making moonshine. At this point, you should have come up with a clear brown liquid referred t as wort or sweet wort. If you choose to ferment on the grain, you will see the solid settle down on the bottom as you let it cool down. If you will utilize a hydrometer, it is also important to have a specific gravity reading of 1.050 which is higher than water. The wort is very prone to contamination at this stage so you have to ensure that it will be free from harmful organisms because this can affect the flavor of your spirit and may cause low alcohol strength or in worse cases, both of these can happen.
Thus, sanitation is very important in this process in order to avoid infection by bacteria and wild yeast that may be present in the air and various surfaces that surrounds you. Although in the mashing process, you have subjected the grains to certain temperatures that are detrimental to some organisms. However, as the wort is cooled down, this produces a perfect environment for these unnecessary organisms to thrive. But this temperature is what you look after so that you can pitch in the yeast that is essential in making a wash with acceptable alcohol content that can be processed in your still. Learn more here
You can protect your work by sterilizing all your equipments such as the fermenter itself and other things that may come in contact with the wort such as the lid, airlocks and mixing spoons as described on Cleanliness and Hygiene page. In summary, the equipments should be immersed in unscented bleach with the formulation of 1 cup bleach to 60 liters if water. This process should tale for at last 30 minutes before these can be rinsed with flowing water. Yet, if you decide to use a soaking solution aside from bleach such as the ones that can be bought at local home brewer stores, it will require you to read the instructions very carefully. Rinsing the sterilizing compound is vital to make sure that it will not destroy your yeast and even you for it can be poisonous as well. Apart from sterilizing the equipments, it will help a lot if you will wash yourself too as you may also contribute to contamination. It will be great idea if you will sterilize all the necessary equipment while your wort is cooling so you can save time. If you can manage to soak your equipments in the soaking agent earlier in time, you may also do so for your own convenience.
At this stage your wort should have a temperature of less than or equal to 30 degrees Celsius. The most optimal temperature to add in yeast would be 25 degrees Celsius because if it exceeds more than 30°C (86°F) the yeast will die and may release awful flavors that will decrease the quality of your final product.
The process of adding the yeast to the wort is called pitching the yeast and you perform this in two ways depending on the kind of yeast that you are using to ferment your wort. You can use liquid yeast and if you wish to do it this way, you must remove it from the fridge few hours before fermentation and allow it to cool to room temperature while you are preparing the mash. Once ready, you can simply pour it in the wort and mix it thoroughly. If you will choose active dried yeast, you have the option to pour in straight to the wort or rehydrate it in a cup of water before pouring it in the fermenter. Usually, dried active yeast comes in single dose sachet and can be purchased from your local home brewer shop. Typically, modern yeasts have no problems when mixed with the wort.
Once the yeast has been added to the wort, no further preparations are needed in order to prepare the wort for the fermentation process. The fermenter should be tightly sealed and then the boiling water should be poured into the airlock. This should be placed in a suitable place where it will be from changes in temperature. Preferably, it should be kept in a cool dark place. This is due to the fact that yeast does not need light in order to take its action. Also, you must be cautious when using barley because barley wort reacts to sun and it will release off flavors.
In performing fermentation, certain interventions are not needed because the fermenter should remain sealed until the whole process is complete. You have to practice much control and avoid opening the lid in order to see what is happening because this increases the occurrence of infection. If you wish to view the action taking place, it is advisable to use a glass fermenter so that you no longer have to open the lid in order to take a peek.
The process of fermentation usually takes 5 to 10 days depending on the type of yeast that you pitch in your fermenter. You can use a hydrometer in order to identify the progress of fermentation, but the most suitable tool to use is the airlock. Initially, when you fill the airlock, the yeast will be held inactive until the yeast rehydrates and come into action. At this point, the airlock will bubble, but you must also take note that some yeast variety can take 6 hours up to 24 hours to become active. When the fermentation process is totally complete you will notice that the airlock will bubble with an interval of several seconds depending on the strain of yeast that you use. Once all the sugars in the wort are all fermented, the bubbling will decline and at this time, it is considered that the fermentation is complete.