Why did my chocolate turn white? This is a very common question people have, but unless you are eating craft chocolate (with no chemical emulsifiers added or other ingredients to prevent this phenomenon), it is not something many people will experience if only eating chocolate made for the masses by the world's chocolate giants. The answer to the question of why chocolate goes white, is due to chocolate bloom; which is classified into two types: sugar bloom and fat bloom. Sugar bloom is from moisture on the surface of the chocolate dissolving the sugar crystals then the sugar re-crystalizing in a different shape. Fat bloom is when chocolate melts and re-solidifies with different types of crystals within the cacao fat forming.
With either type, if a consumer has never seen it before, it can be shocking. Some people will think their chocolate has gone bad, molded, or is old; which is not the case at all. Actually when this happens, your chocolate is completely edible, it just needs to be remelted and re-tempered (which your not going to do with one chocolate bar). Besides the outer appearance, bloom also changes the physical texture of your chocolate making it less enjoyable, but has not gone bad in any way. If this ever happens to your chocolate bar as a consumer, if you don't want to eat it, just use it in your next cookie, brownie, or cake recipe. If you are like us though, our first experience with bloom was when we started making our own chocolate; if your temper is not correct, the chocolate will bloom.
So how do you tell the difference from sugar and fat bloom? The times we have experienced sugar bloom, is always during summer farmers markets. Due to the extreme hot and humid Houston summers, we store all of our bars in a cooler while at the market. When removing the bars from the cooler, as soon as they are exposed to the heat and humidity, condensation occurs on the outside of the bar resulting in a foggy or cloudy appearance on the surface. For fat bloom, the change is not only at the surface but within the bar itself. Most often we see fat bloom with our bars when there is a problem with the tempering process or if a bar is exposed to heat causing the chocolate to melt and breakdown its unified type 5 crystal structure and typically type 4 crystals forming when the chocolate re-solidifies. To understand fat bloom, it is really important to understand that the fat's within the cacao (cacao butter) have six naturally occurring types of crystals and tempering the chocolate creates type 5 crystals only; which gives the chocolate the beautiful appearance and snap; presence or other types of crystals that are not as stable will be physically visible. Tempering and cacao butter crystal types is a whole other article by itself or more so I advise starting with video #12 in Chocolate Alchemy's making chocolate at home series (click here).
Chocolate Alchemy has an excellent video about chocolate bloom here: https://youtu.be/ZeiNycChFwg. John Nanci with Chocolate Alchemy has written many articles available on his website that are truly liking finding gold nuggets for the craft chocolate maker; here is one simple article related to chocolate bloom: https://chocolatealchemy.com/blog/2014/03/13/ask-the-alchemist-64.
We will post some of our one photos of bloom at some point but here are a couple from the internet: