A vessel with a bubbling mead inside.

Ferment

With our Original Gravity (OG) reading taken, it’s time to leave the mead to ferment. There are a few things to keep in mind during a ferment, which we will now cover.

Fermenting Temperature

The temperature at which you should store your mead will depend on the type of yeast in your mead. Check your yeast packaging for the temperature range that is optimal for your yeast. Try to stay on the lower end of the range.

Smaller batches are easier to manage the temperature of. If you’re making batches of 20 litres or larger, we suggest using temperature control.

Temperature control usually consists of using an insulated chamber such as a refrigerator or freezer as well as a heating element such as a heat belt, space heater, or heat pad. The heating and cooling components are plugged into an Inkbird temperature controller, and the probe from the Inkbird is inserted into the chamber. The Inkbird will then maintain the temperature inputted by toggling the heating and cooling elements on and off. This setup allows for a more consistent fermentation temperature.

Avoid Direct Sunlight

Sunlight kills yeast. This is due to ultraviolet light causing yeast cells to break apart. When this happens, nasty off-flavours will be added to your mead. That’s why it’s important to leave your mead somewhere dark while it ferments. A cupboard or towel works well for this purpose. If using a towel, it will act as an insulator and increase the temperature of the ferment, so be sure to account for this.

Nutrient Addition

For meads that have a starting gravity of 1.090 or above, you should add additional yeast nutrients in the form of Fermaid O 48 hours after pitching your yeast. This staggered addition will increase the efficiency of your yeast, speeding up the rate at which it ferments as well as keeping it healthy.

Don’t Count Bubbles!

There are lots of articles online claiming that you can tell when a ferment is over by counting how often your airlock bubbles. This is not true.

There are a number of reasons why counting bubbles is not advised:

  • Your vessel may not be airtight, meaning there are no bubbles in your airlock. A ferment could still be active during this time.

  • Mead can hold CO2 for many months after a ferment is finished, meaning your ferment will finish long before bubbles stop appearing in the airlock.

The only safe way to check if your mead has fermented is by using a hydrometer or refractometer.

Gravity Readings

Every 3 days after pitching your yeast, you should take a gravity reading with a hydrometer. You should keep a log of these readings to track your meads progress.

The gravity should rapidly decrease until reading a final gravity. A final gravity should remain the same over 9 days. If the gravity is still declining, even at a slow pace, you should leave the ferment to finish.

You can reach a final gravity in three ways:

  1. Yeast consumes all fermentable sugars in the mead. The gravity of these meads will be 1.000 or below. This would be considered a dry mead at this time.

  2. Yeast reach their alcohol tolerance. An estimated alcohol tolerance will be stated on the yeast packaging, but yeast often exceed this.
  3. The ferment stalls and the ferment concludes early. This is usually due to either low temperatures, undernourished yeast, or a low pH. Stalled meads can sometimes be restarted by pitching more yeast with some Fermaid O. Stalled ferments can sometimes restart at a later time due to variables such as temperature change. Never bottle meads that have stalled for this reason.
Back to blog