After brewing the Saison earlier this week, I had about a pound of leftover Pilsner malt that was just staring at me. I didn’t have much use for it, so I was going to simply toss it on the compost pile. But then I remembered the expired packet of Munton’s generic ale yeast I had in the fridge.
About a year ago, I thought about using my French press to mash grains for yeast starter wort. I thought the idea was pretty brilliant, but I never got around to trying it. It makes great coffee, and the process for mashing grains is almost identical.
The idea was simple; I’d use my teapot to heat the strike and sparge water, and mash the grains right in the French press’ glass decanter. Then I’d use the screen plunger to strain the wort from the grain. Assuming a rather paltry efficiency of 55%, I plugged some numbers into Beersmith, and estimated I could get about 1000 mL of wort with a starting gravity of about 1.045.
So how did it go?
- I definitely made fermentable wort!
- Using pot-holders to insulate the glass decanter worked pretty well. I only lost a few degrees during the 1-hour mash.
- The mesh screen eliminated the need to vorlauf.
- The yeast fermented vigorously, despite being more than 18 months past its expiration date.
- My actual efficiency was even lower than I expected. The starting gravity was only 1.038, indicating an efficiency closer to 45%.
- The fine mesh screen clogged almost immediately, and made it difficult to drain the wort out of the decanter.
- I was only able to collect about 650 mL of wort instead of the anticipated 1000 mL — probably due to the clogged screen.
This method absolutely works in an academic sense, but fails at being an efficient means of wort production. It’s definitely simpler to boil a little DME and be done with it. But that’s not nearly as much fun.
I like that the scale of the French press is perfectly suited for making just enough wort for a yeast starter. However, the biggest problem is the fine mesh screen. It clogs too easily, and prevents the wort from being able to filter through. I was able to squeeze out more wort by firmly pushing down on the plunger, forcing the wort through the screen. Unfortunately, had I actually intended to use this starter wort, the excessive pressure on the grains probably resulted in excessive tannin extraction.
I still think this idea could work with some modification. The mesh screen is the main problem. If the original screen was replaced with something more coarse, I think this could work pretty well. I’m going to see what I can find at the hardware store, and I’ll probably run this test again.
I can absolutely confirm that the French press makes truly excellent coffee.