Updated: Jun 16, 2020
When I started gathering supplies for my curves class with Rachel at Stitched in Color, one of the supplies listed was spray starch. I tend to have a sensitivity to chemicals, because they tend to aggravate my asthma. As such, store-bought spray starch is not something I keep in my supplies.
I did some research on DIY spray starch options, and I kept coming across suggestions to mix vodka with water and spray it on fabric. The idea behind that seems to be that vodka is made from potatoes, and potatoes have starch in them, ergo: vodka has starch in it. But that didn't square with my understanding of the distillation process, so I did some research.
My wife and I visited a bunch of whiskey distilleries during our enGAYgement, and I've also toured rum distilleries in St. Croix, so we've heard a lot about how alcohol is made. The distillation process involves turning starches into sugars, and then converting the sugars to alcohol. Hard alcohol—including vodka, gin, rum, tequila and whiskey—has 0 grams of carbs or sugar per ounce, because the distillation process removes the sugars and starches. That's the reason vodka is clear, and not cloudy: all of the starch is gone. I conferred with my friend Jenn, who is a molecular biologist and Director of Science Outreach at Bellevue College, and she and her colleagues agreed: there is no starch in vodka.
It's neat to think that vodka makes a good spray starch since it comes from potatoes! But even if the science backed that up for potato-based vodka, many vodkas in the United States are made from 95% pure grain alcohol. While vodka was once made from potatoes, most vodka today is produced from grains such as sorghum, corn, rye, or wheat. Some vodkas are made from potatoes, molasses, soybeans, grapes, rice, and sometimes even byproducts of oil refining (EW!) So there's definitely not anything in vodka that would be starchy.
So. Myth busted: Vodka + water is not a substitute for actual starch. Instead, you want to mix water with an actual starch such as cornstarch or potato starch. You could probably even use tapioca starch, if you have a skin sensitivity to corn or potato. Whatever starch you use, be sure to wash your completed project: natural starches can attract bugs, who will be delighted to nibble on your fabric in their pursuit of the yummy starches you sprayed onto it.
Even if using vodka did have more than a placebo effect, I'd be worried about using vodka (or any alcohol) on my fabrics, because they can make certain dyes bleed. Some bloggers recommend adding a tiny bit of vodka as preservative (since homemade spray starch can go "bad"), and a small amount may also help the spray starch evaporate faster. But don't ditch the vodka altogether! Just save it for a cocktail to keep next to your machine while you sew!
Homemade Spray Starch
Prep Time: 5 minutes
Cook Time: 10 minutes
Total Time: 15 minutes
Yield: 2c spray starch
1 1/2 tsp cornstarch
2-3 tsp water
2 c. water, divided
1-2 Tbsp vodka (optional)
Mix the cornstarch with the 2-3 tsp water and whisk until smooth.
Heat 1 c. water on stovetop until boiling.
Slowly add cornstarch mixture while whisking constantly.
Cook for about 2-3 minutes, whisking constantly. Mixture should be opaque white in color.
When mixture reaches a rolling boil, whisk in additional 1 c. water and remove from heat.
Let cool, add vodka if using, and pour into a spray bottle.
Tips for using homemade spray starch
If you have your iron on high, take care not to scorch your iron or your fabric. Starch burns easily and can potentially ruin your project or leave burn marks on your iron plate.
Store any excess spray starch in the fridge so that it doesn’t ferment or get moldy.
After you spray your pieces with spray starch, move the iron over your fabric without touching it. If there's any excess liquid on your fabric, this can help dry it up so that the fabric doesn't stick to your iron. Ironing damp fabric may cause the fabric grain to distort, which would be a shame after you've cut out your shapes for piecing!
Clean your iron regularly! The starch can build up quickly on your iron. Irons can be cleaned with iron cleaner with iron cleaner or with a solution of vinegar and water.
Wash your finished creation promptly so the starch doesn't attract bugs.