Should the Final 15ml of Pour-Over Coffee Be Removed? Can You Skip the Last Portion?

Once while brewing coffee, a guest nearby asked, "Should I discard the tail end of this coffee?"

The Tail End

After some investigation, I learned that whether to keep or discard the tail end refers to removing the filter cup (cutting off the flow) when there are still 15-20ml of coffee liquid left in the filter cup during the final stage of brewing. Those who use this method of removing the tail end believe that the tail end will have bitter, astringent, and mixed flavors, and removing it can reduce the unpleasant experience brought by bitterness, astringency, and off-flavors.

Is the Tail End the Main Culprit of Bitterness and Off-Flavors?

Many times when people taste bitterness and off-flavors in pour-over coffee, they feel that it's significantly reduced by discarding the tail end during the brewing process. From this, they conclude that bitterness and off-flavors come from the tail end of the coffee.

FrontStreet Coffee learned from several partners who use this brewing method that cutting off the flow generally falls into two situations: The first is to discard the remaining 15-20ml of coffee liquid after injecting the target amount of water (calculated according to the coffee-to-water ratio). The second is to habitually inject 15-20ml more water than the target amount and discard the remaining 15-20ml of coffee liquid.

The difference between these two is that the former's actual coffee-to-water ratio will be larger than planned, while the latter is roughly equivalent to the plan (note the wording is roughly, depending on the brewer's grasp of when to cut off). FrontStreet Coffee tested both situations, selecting washed Yirgacheffe and Brazil Red Bourbon, representing light-medium and medium-dark roast levels respectively.

By tasting and comparing the cut-off tail end coffee liquid, the results are as follows:

This is the result obtained using FrontStreet Coffee's pour-over brewing parameters, for reference only.

Regarding this, the coffee tail liquid from a normal coffee-to-water ratio injection did not show negative flavors such as bitterness and astringency, meaning even if it drips normally into the lower pot, it won't have bitter or off-flavors. The tail liquid from the second method indeed does have some negative flavors, but it's important to understand clearly that this portion of coffee shouldn't have appeared in the coffee in the first place, as the coffee-to-water ratio is already incorrect.

Shift Focus from the Tail End to Parameters

Perhaps many people will say, "The tail end I brew does have bitter and off-flavors." At this point, we should pay more attention to the brewing parameters. Normally, after formulating a brewing plan and implementing it completely, if bad flavors appear in the coffee, then it's either a bean problem or the brewing plan has issues.

The quality of coffee beans does have a significant impact on brewing flavor. For example, like the highest-grade coffee beans from various coffee origins, they basically don't need the action of removing the tail end and won't produce negative flavors. While some slightly lower-quality coffee beans are more likely to produce negative flavors, and in terms of probability, removing the tail end can indeed reduce the degree of bitterness and off-flavors.

In terms of brewing plans, for example, FrontStreet Coffee commonly uses brewing parameters: 15g of coffee powder, injected with 225g of 91°C hot water, with a grind size that has 80% pass-through through a #20 sieve. This brewing does not require cutting off the flow, maintaining a 1:15 coffee-to-water ratio. Of course, sometimes plans don't keep up with changes. "Cutting off the flow" is a response measure taken by the brewer based on their own experience judgment and actual situation, believing that letting it continue will cause coffee bitterness.

In itself, "cutting off the flow" is a means of saving coffee, heavily dependent on the brewer's judgment, most commonly appearing when the coffee powder layer shows blockage, in order to prevent over-extraction by removing the filter cup before it's completely dripped through. But making "removing the tail end" part of the brewing plan adds a bit of uncertainty to oneself (how to grasp the amount you cut off, the accuracy of the coffee-to-water ratio cannot be controlled).

To summarize, although bitterness and off-flavors seem to appear mostly in the tail end, with high-quality coffee beans and the correct brewing plan, it's difficult for bitterness and off-flavors to appear. Therefore, removing the tail end is a method, but you should look for the reasons in the coffee beans and brewing plan.

Important Notice :

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