In one of the original recipes for a 5 gallon BOMM, there was a mix up on units for the measurement of yeast nutrients. That typo has plagued me ever since. Below is the full and correct 5 gallon BOMM recipe:
The BOMM - 5 gallons
1. First, you need to make a starter of Wyeast 1388 a few days in advanced. Add the following to a sanitized 2 liter flask:
-1800 ml of Ozarka spring water
-1/2 cup of honey (SG ~1.04)
-1 tsp of GoFerm
-1 activated smack pack of Wyeast 1388. Activate at least 1 hour, but no more than 2 hours.
-1 cross shaped stir bar (sanitized)
NOTE: If you don't have a stirrer, it will work fine without! You can also make a 1 gallon BOMM and pitch the entire gallon after 3 days. If you are really lazy, you can also pitch 3 activated smack packs (Expensive though!)
2. Place covered but not air locked on a stir plate for 2 days; go 3 days without a stirrer.
3. Add 1 gallon OB honey to 3.5 gallons water. (SG 1.09-1.1)
4. Use a drill powered mixer to mix honey completely. You can do it by hand, but it's very tiring!
5. Add 1 tsp K2CO3. One time addition.
6a. OLD STAGGERED NUTRIENT PROTOCOL - As history shows, this protocol works, but the new protocol (6b.) improves the aroma and body of the mead and avoids off flavors from DAP. DO NOT USE BOTH! Pick 6a. OR 6b.
Add 1 tsp DAP and 2 tsp of Fermaid K.
-Add these again at 1.066 & 1.033 gravity.
-These are nutrients you can get at homebrew shops or Amazon. Fermaid K contains vitamins, minerals, and trace nutrients. Honey is very deficient in nutrients so you need both to prevent fusel production. Diammonium phosphate (DAP) is a free nitrogen source. DAP can add off flavors if added after 1.033. Omit if you missed your gravity!
6b. NEW STAGGERED NUTRIENT PROTOCOL (DLNA)
Add 2 tsp of Fermaid K upfront only.
Add 2 tsp of Fermaid O upfront, at 1.076, and at 1.043 gravity.
-These are nutrients you can get at homebrew shops or Amazon. Fermaid K contains vitamins, minerals, and trace nutrients. Fermaid O is an organic source of nitrogen. Honey is very deficient in nutrients so you need both to prevent fusel production.
7. Stir again to aerate.
8. Add your 2 liter starter of Wyeast 1388.
9. If needed, add water to 5 gallons.
10. No water in airlock for 1 week.
11. Degas daily.
12. Ferments dry in about a week, clears in 3-4 weeks. You can cold crash and/or use Superkleer to speed up clearing.
The object of the starter is to build up enough yeast numbers to ferment your mead very quickly and cleanly. If you do not have the equipment necessary to make a starter, you can make a 1 gallon BOMM to pitch into 4 additional gallons. After adding yeast to the 1 gallon BOMM, wait 3-4 days before pitching into the additional 4 gallons.
All the normal Post Fermentation options stated in the 1 gallon recipe or on this site are viable. Just scale honey additions or spices linearly to your batch size.