Bypass brewing in home brewing methods/suggestions?

#1: Post by **TomC** » April 7th, 2014, 5:00 pm

Has anyone played around with pour over style brewing that incorporates bypass brewing and enjoyed their results or found anything conclusive worth sharing? I know it would simply dilute the beverage strength, but I'm curious if it could be employed as a simple way to improve flavor perception in a more separate flavor sort of way by incorporating coarser grinds and slight under extracting.

This isn't a concrete idea I have rattling around in my head, so I don't have a specific thing to nail down to discuss. But I'll do my best. On certain coffees, an over extraction, either from a finer grind, longer brew slurry time, or more water, can deliver more dissolved solids into the cup. In this, there's going to be the easy to dissolve sugars and acids. Towards the end (and pulling references from others here, not my own rock solid data) more of the harder to dissolve caramels and compounds are allowed into the brew.

We've talked about some coffees having "static" in the caramels, that doesn't elevate the cup, but slightly mask other perhaps more desirable flavor notes, or detract from isolating more specific desirable flavors.

I'm thinking in certain coffees, coffees that have incredibly dynamic, even unbalanced but otherwise surprising and fantastic key flavor compounds, (Guatemala Acetenango Geisha comes to mind), it would serve to updose, grind a bit coarser, brew with a slight reduction of water (say a 15:1 vs a 17:1 ratio), but then, slightly dilute the beverage with "bypass water". It stands to reason that only certain coffees would benefit from something like this, and it might allow for more flavor separation and a better brew that isn't muffled by slightly over extracted caramels that just add "static" to use Another_jim's description.

Some coffees seem to require the exact opposite. A complex Kenya that has a mile long list of flavors that add up to a balanced but potent brew, I find, always benefits from a slightly finer grind, and slight over extraction to add a bit more of those late extracting, or hard to extract caramels, which then help provide a sweet background to all the spice and pop in the cup.

Then there's coffees that live somewhere in the middle, a coffee like our recent Costa Rica El Centro Black Honey. It's great coffee, with wonderfully sweet chocolately fudge brownie and vanilla custard notes, but not much else. I don't know if there's tricks that pop that cup better or not, other than proper rest and a developed roast, which fall out of the realm of what I'm discussing here. But it's sugars and caramels make it so wonderful.

But has anyone tried playing with a coffee where the late extracting caramels can be left behind, and the beverage just slightly diluted with bypass water? I think this would work best with a coffee that is incredibly snappy, unbalanced and dynamic, but in a good way e.g. a insanely great floral Geisha with mind blowing acidity. Well rested to insure full solubility, but ground slightly coarser and heavily updosed. Then, brew it with a low brew ratio (15:1, maybe even down to 13:1) and then a slight dilution of plain hot brew water that bypasses the slurry. This would be slightly more wasteful, but worth it if the resulting beverage is much better.

I've done this with some coffees with pleasing results, with coffees like the ones I described above. I'm just curious if anyone else has done it and would be willing to share their findings.

#2: Post by **endlesscycles** » April 8th, 2014, 8:41 am

I bypass all the time with 1gal pour-overs at market. I can bypass the filter but fill the surrounding basket, which allows me to hold the pre-wet water in the brew bed a little longer as the basket orifice is clogged with bypass water. I do this to get more a thorough saturation leading to a better extraction.

I'm dubious that flavor components can skip order of extraction, which is related to molecular size and solubility. While we know that 20% isn't always the same 20%, I only believe that can be affected by grind size distribution and the dynamics of the brew bed whether finer particles are given the opportunity to over extract.

That said, the whole reason I bypass is to prevent fines migration and their eventual over-extraction as well as non wetting of coarse particles and their eventual under-extraction, so obviously I'm shaping the flavor profile in doing so.

#3: Post by **yakster** » April 8th, 2014, 9:52 am

I bypass brew only in the most basic way: when brewing a large batch in the Chemex/Kone or Kalita and my pour time will exceed my target by a large margin, I just add the balance of the water to the brew, bypassing the filter bed. I don't notice a difference, but I haven't done a comparison.

#4: Post by **jaybar** » April 14th, 2014, 3:21 pm

There is someone on Coffeegeek who goes by johnnyb3, who has talked about this several times. You might want to reach out to him.

Jay

#5: Post by **johnster** » April 27th, 2014, 1:19 pm

Couldn't you achieve the same in a more predictable way by sifting the beans to remove the fines?

April 27th, 2014, 7:59 pm

No, because you aren't removing fines, you're just keeping particles larger than the sieve's holes. Fines are much, much finer and the term "fines" gets too broadly, and I think, inappropriately applied to discussions. What would change things is removing the smaller particles on the far end of the bell curve, up to a point and re-approaching it that way.

But grind particle size evenness may not even translate to a better resulting cup. It was mentioned here previously somewhere by Yakster I believe, that Nick Cho and Trish decided to pull the EK43 off the brew bar, and go back to the Guatemala, because ultimately, they were just happier with the resulting beverages that came from the Guatemala. In his words " Taste> Trends".