Why French pressing is a thoroughly unpleasant experience for all parties involved
French pressing squashes cells under loads of pressure until they go POP. The press consists of a hydraulic pump and a piston in a hollow metal cylinder which contains the cells. It’s a bit like making coffee in a cafetiere but much, much, worse. The cells are pushed through a valve where the plasma membrane/cell wall just can’t take it any more and breaks. Apart from being an excellent torture device for naughty cells, French pressing is useful for the isolation of various cell gubbins including membrane vesicles. Unfortunately, French pressing is not particularly enjoyable for anyone.
If you’re a non-bio-scientist and didn’t understand a word of that, it doesn’t matter – the point is, I have to do it, and it is horrible, and I am going to tell you why.
- Things can get incredibly messy. There is huge potential for cell juice to come squirting out of various holes at great speed if you’re not careful enough. The first time I ever French pressed, the whole thing exploded as I was lifting it onto the hydraulic pump, coating me in gloopy green bacteria. I even managed to swallow some (it tasted of soapy soil).
- The pump is noisy, and it takes ages to do one sample. It emits a high pitched mechanical whine, a bit like if you pitch shifted up the sound of a chainsaw cutting through a noble old oak tree. Everyone peacefully working in the lab has to work through this constant grating noise. The whole squashing process happens twice or more, once you think the press user has stopped, the racket inevitably starts up again a few minutes later. Our French press only does batches of 40ml, so woe betide anyone who has any more cells to do than that.
- I am pretty feeble, and the French press cylinder is pretty heavy. I’d compare it to trying to balance 40 house bricks on one hand. Once you’ve put your cell sample into the apparatus, you have to lift it onto the pump whilst carefully (gingerly) holding it so that your precious cells don’t dribble (explode) out everywhere.
- The jokes get old. No, the apparatus is not named after a sort of torture device used during the French revolution. Hur hur, do the French call it English pressing? French press – that’s what they call coffee makers isn’t it, are you going to drink your cells lolllllllllll. Even more frivolity occurs if you happen to have someone from France in your lab. It’s actually named after a bloke called Charles French, which is rather disappointing really.
- The poor little bacteria get squashed to death. I typically splatt my cells at 3,000 psi, which is just over 204 atmospheres of pressure. Just imagine having all that sitting on your head! I expect you’d be greatly vexed.
I am now going to go back on everything I’ve said and declare that I actually love French pressing. It is a means to an end and I love my science. This is most likely because I am a n00b PhD student. I haven’t been beaten down by years of tedium and failure yet. Also, squashing your cells until they burst is a great form of stress relief.
Thank you for listening. Goodbye.