bomb notes

when i first discovered bath bombs, i thought, "how cool". i first experimented with the basic recipe of 2 parts baking soda to 1 part citric acid. using witch hazel to moisten, i had success with my first attempt. this was too easy. if it is this easy, why all the complicated recipes, most of them calling for cornstarch and oil and requiring long drying periods. i continued to research only to run into more discord and contradictory data ...no definitive statements, only personal opinions, so here's mine. first i'll start with the facts i do have:
	•	the purpose of a bath bomb is to provide an interesting visual as it dissolves -- the fizzing; the more robust, the better.
	•	in the process of dissolving, it dispenses fragrance into the air, and deposits its contents (which may include coloring, oil, emulsifier, baking soda, and/or cornstarch) into the bath water.
	•	since all of the results, save the prolonged effervescing, can be accomplished by simply adding the ingredients (in the form of loose "bath crystals") to the bath, all the hubbub is about how and to what extent the bomb "fizzes".
from this, i deduce the only reason to use the oil/cornstarch method is:
	•	to add these extra ingredients to the bath, or
	•	it's easier to control the inadvertent activation of the fizzing, since oil doesn't set off the fizzing reaction.
in my research, i've come across some interesting bit of information (contained in the "notes" below), which are beneficial in deciding how to construct and what ingredients to include in a bath bomb. i've made a few bombs using oil and cornstarch, with and without epsom salts, and have found no significant benefit to this method. i retain my preference to "variation II" ...as described in "bath bombs, oils, and salts". a note on oil: with the oil/cornstarch method, the oil, which is the moistening ingredient, ends up as oil in the bath, resulting in a slick on the surface of the water ...coating the skin and contributing to the bath tub ring. the best way to add oil to the bath is to use turkey red oil (as described in "bath bombs, oils, and salts"). however, this oil seems too thick to be used in making a bomb. but, (and this is a yet untested theory), it seems that if this were, say, 50% of the total oil, maybe it could be used and all the oil would disperse into the water. a note on cornstarch: i have read that this is used because if causes the bomb to float. it's said the cornstarch also adds a silkiness to the water; i didn't notice any appreciable difference. there are some sources that allege that cornstarch fosters yeast infections and can interfere with skin conditions, while others claim this not to be so and that it's actually great for you skin. a note on epsom salts: many state that the epsom salts, (as well as the citric acid), should be ground (in a coffee grinder) to a powder. this is supposed to enhance the effervescence, however, i personally have found no difference from using the granulated form of either. the addition of the epsom salts is supposed to exacerbate the effervescence as well as cut down on the drying time of bombs using the oil/cornstarch method. as stated in the "note on drying", i found my drying time to be considerably less that 24 hours, which the epsom salts may have influenced. a note on drying: the oil/cornstarch method requires a 24 to 48 hour drying period. in my experiments with this method ...the formulation i used included 2 parts epsom salts, i found the bomb seemed to be dry long before this, but i still allowed it to sit for 24 hours. since the finished bomb still remains somewhat fragile, there are some recipes that suggest spritzing the surface with witch hazel to form a hardened crust. caution, this could set off the fizzing action. a note on size and volume: i've read recipes that product bombs in ball form with diameters up to and in excess of 3 inches, and weighing up to 6 ounces and more. even allowing for an adjustment of fragrance and color, i personally feel that this kind of volume puts way too much "stuff" in the water. however, a well-known commercial producer of bath bombs ("lush"), makes them in this large "baseball-size" format, so, go figure. the bombs i make, and prefer, have a 1/3 cup volume (i actually use the measuring cup as the mold), with a weight of approximately 2.75 to 3 ounces. a note on color: if you use a water-based color, it'll color the water. if your intention is just to color the bomb, use a colorant that's not soluble in water, but be warned, this will only contribute to any "ring" around the tub ...especially in the presence of any oil floating on the water surface. this is where an emulsifier is beneficial. a note on orris root powder: this is an excellent additive (1/2 to 1 tsp. per bomb); it helps the bomb to hold the scent. this would prove beneficial if the bomb wasn't to be used right away. a note on stability and shelf life: bombs should be stored in a cool dry place. humidity can set off the reaction (even though you don't see it fizzing), so that when you use the bomb, it just "lays" there; not fizzing. in any event, the bomb shouldn't be stored for too long, lest it lose it's ability to fizz. I've used bombs up to 2 months old that were still "active".