Here’s a question for all you science-y types out there–do you think laboratory filter papers are food-safe? Since I seem to have an issue with acid reflux (short version: I don’t really have “heartburn” per se, but I was having trouble swallowing and an upper GI scope indicated irritation that the gastroenterologist said was from reflux), I’m trying to stay away from caffeine and acidic foods. I love coffee, and I’ve found that the cold brew method creates a much milder-tasting cup that I’m sure is easier on my stomach (I use decaf). The only problem is, filtering the stuff out by gravity takes forever and invariably makes a mess. So I requested for my birthday a filtration setup that I want to use to vacuum filter it instead, and my mom bought it for me. (Thanks, Mom!)

So far I’ve just been using regular basket-style coffee filters–actually I’ve been using a regular kitchen funnel too because the cheap Buchner funnel I asked for had a break between two of the holes and in any case wasn’t fully glazed, so I’m afraid it’s not food-safe either (I’m reminded of how they always tell you not to eat off a glazed china plate that has a hairline crack or chip). Consequently I’m going to return it and get a more expensive fully glazed one. Anyway, this setup is faster than gravity but not by much. I can’t seem to pull a measurable vacuum.

So tonight I tried using some leftover grounds in the basket filters with the actual Buchner funnel–I’m not going to drink the result, I just wanted to see how it would work. Again better than gravity and a little better than the same basket filter in the kitchen funnel. But what worked far and away the best was to use the laboratory filter circles that came with the kit. I pulled 300 mmHg vacuum and sucked all the liquid through in no time.

The problem is, I can’t imagine they’re food safe (they’re not made for that purpose), and obsessive googling reveals no obvious source of food grade filter circles. I considered percolator filters but they don’t seem to come in the 110-mm/4.5″ size that I need. I’m going to try just cutting circles out of the basket coffee filters (maybe the fluted sides are making it so they don’t completely seal), but I’m skeptical that this will work. I feel like the filter media is just too coarse and air leaks through it so it can’t really pull a vacuum. Is this possible or am I full of shit? I’ve found people claiming they use these cut-out coffee filter circles in this setup and they work great, but based on my observations of the full basket filter, I am not optimistic.

So, what do you think? I’ve found threads online where people obviously bought the same or a similar setup and are happily using the lab filter circles to make their coffee, so maybe it’s actually OK. I doubt it, but here’s hoping.

Thanks in advance for any input you might have! This would be really kick-ass if it would work.