Refrigerate raw honey for long term storage.
from Keith Kimes, Kimes Apiary
I have received a complaint that some Harkins Slough Wild Flower honey harvested 7/8/15 is starting to ferment. Raw honey is at risk of fermentation since it is not pasteurized. I recommend that consumers store their honey at room temperature if it will be consumed within 3 months. If your container of honey is too large to be consumed within three months then it should be divided into smaller containers and those that are not in use should be stored in the freezer or refrigerator, only the container of honey in use should be stored at room temperature. Please check your honey and if it has crystallized and has developed white feathery patterns such as this picture then it is starting to ferment, and should henceforth be refrigerated to stop the fermentation. The honey is still good to eat but if fermentation is allowed to continue it will change the taste. Read more about fermentation of honey at http://kimesapiary.com/honey-fermentation/.
Raw honey has not been pasteurized so it contains live yeast. When the moisture content of the honey is high enough the yeast will grow, fermenting some of the sugars, making more yeast, alcohol, carbon dioxide and acetic acid all of which will change the flavor of the honey over time. When honey crystallizes the moisture content of the remaining liquid increases and fermentation becomes more likely. Place the glass jar of honey in hot water to re-liquefy it. If you wish you can allow the honey to get to 160 degrees during the re-liquefying process to pasteurize it but then it will no longer be raw. If you prefer crystallized honey you should store it in the refrigerator. The yeast can not grow at temperatures below 50 degrees.