Cold drip adventures
Ben here, the (relatively new) store supervisor of Di Bartoli Home Barista Centre in Sydney. How is everyone?
I'm enquring about cold drip coffee and the method behind making a perfect batch of it. We have a Tiamo cold dripper which, while lacking a lot of bells and whistles, does the basic job of slowly dripping cold water over coffee grounds just fine. I can run a batch of it, however I nearly always end up with the water channelling through sooner or later, leaving quite a few coffee grounds in the final batch and a compromised taste.
My ratio is 60g of light-roasted, coarse-ground coffee (finer than a plunger but coarser than filter) to 600ml of cold, icy filtered water.
I put everything together, pop a filter on top of the grinds, presoak the grinds, then slow the drip down to about 1 drip every 1.5 seconds. The first coffee drip is usually about 30 minutes after slowly the drip down.
Now here is where I run into problems. The water tends to back up over time, to the point where I have at least a few CM of water sitting over the grinds and the filter sitting on top.
I've read many methods and looked at many tutorials on YouTube. I'm wondering where it is that I am going wrong.
Thanks and regards
Hi BenJohn, I wouldn't call myself an expert in cold drip but what you describe is quite normal from what I have seen. <Caveat before reading on - this is written by a simpleton>
The coffee gets to a stall point where it reaches saturation and starts to pool. At this point I back off the drip rate until it stops pooling. After about 1 hour you will notice the coffee start to drip faster and will get to a point where it drips as fast as you would like it. My theory is that the coffee goodness is extracting itself from the beans and becomes very thick. After a while most of the extraction is done and there is not too much left to restrict the water flow.
I'm sure there are smarter people out there who can explain better but my end result is a great brew so I haven't looked into the science too much.
Happens to me sometimes & I thought it must be fines getting washed down there. But I don't know.