How to avoid back sweeteining
The best choice for most beverages is to avoid excessive dryness in the first place. Dryness can be avoided by using fewer fully fermentable sugars such as table sugar, or by using a less attenuative yeast. See the Dry article for more information on the causes of dryness and how to avoid it.
Back sweetening agents
Once a batch has fully fermented, there are two ways of back-sweetening: with fermentable or unfermentable sweeteners.
Back sweetening with unfermentable sweeteners
The easiest way to back sweeten is to add an ingredient that adds sweetness but is not fermentable. This can be either a complex sugar, such as lactose, that cannot be fermented by most ordinary yeast, or an artificial sweetener, such as Splenda, that gives sweetness without sugar.
Suggested amounts for sweetening a batch:
- Lactose: 1 pound per 5 gallons
- Splenda: 1/3 cup per gallon
Back sweetening with fermentable sweeteners
It is also possible to back sweeten a batch with fermentable sugar, although this requires more care to avoid carbonation or overcarbonation. Adding fermentable sugar to a beverage with yeast in it will restart fermentation. There are two ways to handle this situation.
With some beverages, especially mead, extra fermentable sugar can be added and the fermentation can then be allowed to proceed normally. This will lead to a higher alcohol content, but as the gravity increases, the attenuation of most yeast strains worsens and the proportion of unfermentable sugar therefore increases, resulting in greater overall sweetness despite the higher alcohol.
In the alternative, the yeast can be removed or killed before the sugar is added. Filtration can be used to remove as much yeast as possible, or campden tablets or another agent can be used to kill the yeast and any other organisms that would feed on the new sugar.