I don't like that recipe too much!..
-"Boil 2-4cups of water in a pot"
-"Stir in 2-4 cups of sugar to the boiling pot"
Yeast don't handle better than 25-30% sugar by weight, it screws with their osmotic pressure.. And baker's yeast can't do anything with any amount above 25% sugar since it can't handle more than about 14% abv (which is what a complete 25% fermentation should produce).. More sugar than that will slow down the activity or stall it, then go to waste when the yeast die off from alcohol.. I'd put 4 cups into a total of 4 L (or 1 gallon).. BUT sugar alone isn't good.. Yeast are built from more than carbon and water, so they need something complex like mollasses, potato water, oatmeal etc in there too.. I use stuff called diammonia phosphate to energize too, but thats not really needed.. Teeny amounts of high N fertilizer can do that too..
-"Clean a 1 gal juice or milk jug, poke a small hole in the top of the cap."
'Clean' is important, especially if you want reduced odor, and more potable alcohol.. Rinse your jug in a 5% bleach solution for 30 minutes, then rinse very well..
You don't need to boil the water.. Its better to keep it below boiling to retain more O2, but the heat makes mixing/dissolving way easier.. On that note, you want to agitate the crap out of this to get as much oxygen dissolved in the beginning as possible.. (I use a cement mixer on an electric drill for a few minutes as it cools..)
-"Add a small amount of water to the jug and ~1/8 tsp of yeast and gently shake. Add a pinch of baking soda."
Baking soda?? You want acidic conditions around pH4.5.. My yeast starters get a pint of 105°F dechlorinated water, 3 tsp of sugar, a few drops of mollases (yeast need vitamins you know), and a squirt of lemon juice.. Acidity is preferred by yeast, and helps keep bacteria at bay..
This starter is then oxygenated like a mad man and left in warmth for a few hours.. This stage is totally optional, but improves fermentation designed for drinkables.. It also makes things faster after they get rocking..
-"Let cool. It should be still warm, but not too hot, or it'll kill the yeast."
80°F is best for quality, but you can push them faster up to about 100°.. They'll die at 120°, and they get really slow colder than 70°F.. They do best with fair stability.. But if your mix is potent you should cool them down a bit when you hit 12-13% alcohol if you don't want the action to stick.. Really though, potent is dumb for this.. Fastest action will occur when aiming for ~10% abv (1Kg brought up to 6L with water)..
-"Add sugar-water to jug, and gently shake."
Gently?? Pummel as much O2 as you can into that mix.. You should also drop the pH with lemon juice, or creme of tar tar etc at this point..
Using my methods I can ferment a full batch of rum wort to 14% in 3 days.. I ran through the numbers in post #68 here..
Just remember, sugar IS NOT yeast food.. Its like yeast meth..
They use it to get O2 when its otherwise not available.. Healthy reproduction requires a balanced diet, and the vast amount of your yeast will actually be born in your bucket.. Yeast population can double in 3 hours... And don't forget that you can reuse yeast sludge from the bottom..
PS Yeast will work alot faster with dechlorinated water, so let your tap water sit a few days if your municipality adds chlorine.. If they add chloramine instead, you need peroxide, or something similar to remove the more stable chloramine..