This will go over the main uses of step feeding and how to properly step feed a mead. This includes why step feeding can be useful, when to add more honey, and how to do nutrient additions.
Step feeding is adding honey throughout the duration of fermentation in steps which will continually add more sugars for the yeast, but maintain a lower gravity reading than you would obtain by adding the entire amount at the beginning.
There are three primary reasons to step feed a mead.
It yields a lower starting gravity, which means less stress on the yeast during fermentation. This will make for happier yeast, and, under the right circumstances, can help produce finished, drinkable mead faster.
Step feeding helps the yeast push past the expected ABV tolerance of the strain. This is generally only a 3-4 percent boost, but can be useful in coaxing yeasts like EC-1118 above 20%.
You can use step feeding to make sweet mead without the use of stabilizing agents or pastuerization. This is done by step feeding until the yeast reach their tolerance, and then continuing to sweeten to the desired level.
Pushing a yeast beyond its normal alcohol tolerance can be a negative, depending on your goals.
Step feeding is not a way to make a lower ABV mead without stabilization methods.
Make sure to keep track of total honey added and total volume. This calculation is the only ways to determine the ABV of a step-fed mead, excluding lab testing.
Have an end result in mind when you start. This plan should include your ABV and final gravity goals, and some estimate of how much honey you will have to add.
Determine your goals for the resulting mead.
Mix up your original must to an approximate OG of 1.080-1.100. proceed with preferred SNA and degassing schedule as done for a normal mead.
Once the must has dropped 30 points (ex. 1.080-1.050) add back 30 points worth of honey. Add the first half of nutrients for the equivalent of a 1.030 must (0.83g/gal Fermaid O or equivalent of 35ppm YAN). Continue to degas as normal.
At 24 hours after check gravity and add the other half of nutrients.
Once must has dropped 30 points again repeat steps 3 and 4. Continue to repeat this process until desired amount of honey has been added.
Allow the batch to finish and have a stable gravity reading for a week.
Continue with the batch as normal for aging and clarifying.