The Must should now be sitting in a cool location, approximately 65-70°F, away from any light. Some activity should be noticeable within a couple of hours of the yeast addition, but this may take a little longer. Be patient. The yeast are going through the lag phase before they start their growth phase, so very little in the way of activity may be observable. By way of reminder of the lifecycle of the yeast:
Lag Phase: The period during which the yeast are acclimatizing themselves to their new environment, and taking in the nutrients they need to grow and reproduce. This can take anything from a couple to a few hours depending on gravity, acidity, temperature, yeast population size, nutrients, etc. The end of the Lag phase is marked by the formation of Krausen, a layer of foam on top of the Must. At this point, the addition of some nutrients may be beneficial. Recommended dosage is 2/3 of a teaspoon (3.5 grams) of Fermaid K and 1/3 of a teaspoon (1.5 grams) of DAP for a 5 gallon batch.
Growth Phase: The yeast begin to multiply, exponentially, until the nutrients are depleted. This is the period during which aeration is important (see below).
Fermentation Phase: The yeast switch from aerobic to anaerobic metabolism, which means they get their energy and oxygen from the sugar (in this case, the honey), and produce ethanol.
To avoid stressing the yeast during their growth phase, it is important to provide them with the oxygen they need. Aerate the Must a couple of times a day for the first three days by using an aeration stone, shaking, or stirring with a Lees stirrer. Make sure you sanitize whatever equipment you are going to use before putting it into the Must. Aerate for 2 to 5 minutes depending on the method, and then cover the Must again. WARNING – There will be CO2 dissolved in the solution that will begin to bubble out when you begin to aerate the must. This can sometimes result in a geyser effect that could spray your walls and ceiling, and will result in the loss of some of the must. To avoid this, gently agitate the liquid to expel the CO2 before you begin to add the oxygen. This is particularly important if you are using the shaking method.
Bubbling through the airlock should start in earnest on approximately the second or third day. This is the fermentation phase when the yeast are converting the sugars into alcohol. Nothing is required at this point except to leave it be. Check in on it every couple of days to see how active the bubbling is. As soon as it slows to approximately 1 bubble every 30 seconds, it is ready to move onto the next stage – Racking.
When fruit is being used as an ingredient, it has the habit of floating on top of the Mead, creating what is called a Cap. This can cause a couple of issues with the fermentation, the most crucial of which is the potential for contamination. When the cap sits for an extended period of time on top of the Mead, it can begin to dry out, creating a crust on which mold can grow. This mold will then contaminate the Mead, creating off flavors. The cap can also restrict the bubbling of the carbon dioxide, which will build up in the Mead and slow down the fermentation. To prevent the cap from drying out, and to aid in the release of the CO2, the cap needs to be “punched” down a couple of times a day. This requires nothing more than to gentle stir the fruit back down into the Mead using a sanitized spoon.
The purpose of racking is fourfold:
- To stop fermentation by removing the Mead from the yeast and adding Sulfites and Sorbates.
- To remove the Mead from the Lees (layer of yeast on the bottom of the fermenter) so as to avoid a yeasty flavor imparted by the breakdown of yeast cells before bulk aging.
- To add additional ingredients for flavor during secondary fermentation.
- To help clarification by removing the Mead from the Lees before bottling.
It is absolutely vital that the Mead not be mixed with too much air during racking as this will introduce oxygen that will affect the flavor. Also, as always, make sure all of the equipment that will be coming into contact with the Mead is thoroughly sanitized.
1. If your purpose for racking is to stop fermentation and to clarify the Mead, put the carboy into a fridge for a week. This will help a lot of the suspended matter to drop down into the lees.
2. Move the full carboy up onto a counter or table at least a day before you intend to rack. Any yeast that is disturbed will have time to settle back down into the lees.
3. If you intend to rack onto fruit, spices, oak, sulfites, sorbates etc., add them to the secondary fermenter before racking the Mead. You do not want to find that you have overfilled the secondary and do not have room for the additional ingredients.
4. Siphon carefully (see Chapter 16) taking a small sample to test the specific gravity and taste.
5. If you can, blanket the Mead in a small amount of carbon dioxide to help prevent oxidation.
6. Seal the secondary fermenter with an airlock.
It is important to note here that it is not necessary to rack the Mead before you bottle it. Racking is helpful in clarification and when you are adding ingredients or back-sweetening. It is possible to leave the Mead in the fermenter right up to the point that you intend to bottle, but you run the risk of transferring the yeast as well.