Name: Dawn
Message: Is it possible to store dye once it's mixed?  I mixed it by the gallon and stored it in my basement for about a month.  The last batch of tie dyes turned out pretty faded.  Do I need to mix it "fresh" for each batch of shirts?  Thank you!

It depends on what type of dye you're using. The acid dyes used on wool and silk can be stored in solution for a long time. You're probably using fiber reactive dyes, such as Procion MX dyes, though. Fiber reactive dyes have a definite shelf life, once they have been dissolved in water.

The temperature at which you store your dyes makes a huge difference in how long they will stay good. Procion MX dyes will stay good for at least a couple of weeks at air-conditioned room temperature, 70° to 80°F, but they will go bad more quickly if left outside in hot weather. They will stay good for many weeks longer if stored in a refrigerator. They will go bad within hours if stored in a hot car in the sun with the windows rolled up!

Your dyes have to be mixed in neutral-pH water to last long, however. If your water has a high-pH (the opposite of acidic), they will go bad more quickly. If any trace of soda ash gets into the dye, it will go bad more quickly.

If you want to use fiber reactive dye that lasts longer after it is mixed with water, you can try a different type. Cibacron F dyes (sold by PRO Chemical & Dye as Sabracron F dyes) will stay good for at least six months after they are mixed with water, probably longer.

Many people mix their Procion MX type dye with urea for tie-dyeing. Urea does not go bad very quickly, but if it has aged enough to produce an ammonia-like odor, it will interfere with your dye reactions. When I mix dyes that I plan to keep for a long time, I do not add urea. This is not a very important factor if your urea is reasonably fresh, however. The dye itself will usually go bad much more quickly than the urea.

Unless you can refrigerate your dyes, I recommend that you mix only as much as you can use up within a week or two. If you are storing the dyes in an unairconditioned space during the summer, mix the dye powders with water no more than one or two days before use.

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