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Pre Ground Quality Grinder vs Blade Grinder

We asked the question: "Would you rather: brew fresh ground one week old coffee from a blade grinder or one week old pre ground coffee from a quality burr grinder?" "Is freshness of grind or quality grind for extraction better? Has anyone tested this blind? Interested to know results. Based on flavor."


Our good friends at Entimos Coffee were up for the challenge. Here are their results. Enjoy!

Pre Ground Quality Grinder vs Blade Grinder
The prevailing notion in specialty coffee is that fresh roasted coffee ground just prior to brewing is best... right? Simultaneously, we also understand that coffee ground properly (consistent in particle size) is also important. Knowing that most consumers and coffee drinkers do not have adequate grinders but instead rely on the common blade grinder, we decided to perform a simple experiment. The question: Is it better to have freshly roasted coffee that is pre-ground with a high quality burr grinder for brewing later OR coffee that is ground just prior to brewing but with an inconsistent blade grinder?

EQUIPMENT 

Coffee Guatemala Santa Clara
Entimos Coffee Roasters (2- 12 oz. bags)
Grinder Equipment Baratza Prescio Mr. Coffee Consumer Blade Grinder Brewers-Bonavita BV-1800TH Brewers (quantity: 2) Chemex Glass Handled Able Brewing 18K Gold Kone Coffee Filter (quantity: 2) Chemex Brand White Filters
BREWING PARAMETERS Coffee: 45g Water: 750g
Brew Time: ~4 min. *Parameters developed for Kone as recommended
by Able Brewing

EXPERIMENT A PROCESS 

Our coffee was roasted seven days prior to this experiment to possibly replicate the time it would take for an average consumer to purchase or receive a bag of specialty coffee from their roaster of choice. Each bag was carefully weighed to 12 ounces. One bag was pre-ground on the day of roast for pour-over using the Baratza Prescio. The other bag was left as whole bean and both bags were sealed in gusset lined kraft coffee bags with degassing valves and stored properly for the day of the experiment. We decided to use the Bonavita BV-1800TH (SCAA approved) for brewing to eliminate any differences in discrepancies between individuals and their specific manual brewing techniques, which could skew the results of the blind taste experiment. The Bonavita also allows us to simultaneously brew both blade and pre-ground coffee. A total of four people were included in the experiment; 2- coffee roasters, 1-barista, 1- coffee consumer. Each round of brewing was performed blind. One person was designated to brew the coffee and the other three were allowed to blindly taste COFFEE A and COFFEE B to determine which cup
they preferred based solely on taste. Although some of us went into further detail on the characteristics of each cup (acidity, body, etc) than others, we were not looking at getting that in-depth. We were only looking for which coffee “tastes better” or which coffee was preferred.

EXPERIMENT A RESULTS 

Round 1:Brewer: Matt Brewing Filter: Kone

Coffee A (pre-ground): 3 Notes: nice mellow body, caramel, buttery, light sweetness through finish, faint sourness 

Coffee B (blade): 0 Notes: no acidity, indisguisable note characteristics, tea like, under-extracted 

Round 2: Brewer: Matt Brewing Filter: Chemex Paper Filter 

Coffee A (blade): 2 Notes: caramel, buttery, light, lacking rich flavor profile 

Coffee B (pre-ground): 1 Notes: twinge of bitterness in cup, dark chocolate, grapefruit

Round 3: Brewer: Tim Brewing Filter: Kone 

Coffee A (pre-ground): 0 Notes: light caramel, slight bitterness, dark chocolate, faint flavors, generic taste 

Coffee B (blade): 3 Notes: butter, chocolate, more intense flavor than Coffee A, grapefruit 

Round 4: Brewer: Tim Brewing Filter: Chemex Paper Filter 

Coffee A (blade): 1 Notes: light flavor, tea like, faint notes, no real acidity or finish 

Coffee B (pre-ground): 2 Notes: Citrus, dark chocolate, caramel, similar to Coffee A 

*Results express the overall preference of Coffee A vs. Coffee B for each round

DISCUSSION: 

As indicated by the results there was no clear favorite between blade or pre-ground through all four rounds which surprised us a bit. The variances in coffee notes and overall taste between each grind method were negligible at best.
Neither cup was great in any round but we forced ourselves to come back to the question, “Which would you rather drink?” We could safely say for each round most cups had some specific distinguishable characteristics to the coffee but overall there was no single method that stood out as the primary method to choose. We attributed the results to a possible combination of several things. We had two different people brewing between rounds 1 & 2 vs. 3 & 4 who each used the blade grinder differently. It is near impossible to be consistent from grind to grind, let alone person to person when it comes to a blade grinder. The inconsistency of the blade grinder in each round inherently played into the differences in preference and overall taste of each brew method.
As a side note, we were a little impressed at how much aroma was retained in the bag of pre-ground coffee upon opening it. We wondered how the grounds would change now that they were in an open bag. After much discussion we decided to perform the experiment again but to wait a few days and do it in a different way.

EXPERIMENT B PROCESS

In Process B, we retained all of the same brewing parameters as the previous process but instead set up as a blind “cupping”. Nine cups were laid out and numbered 1-9 on the table. Each cup was filled with either Coffee A or Coffee B and cupped blind again solely based upon preference of taste. We then chose which cups 1-9 we liked best of the nine. This preference was a Yes or No decision. Was the cup good? Yes or no...

EXPERIMENT B RESULTS CUP NUMBER

C1 BLADE (1 VOTE)

C2 BLADE (0 VOTES)

C3 PRE GROUND (3 VOTES)

C4 PRE GROUND (3 VOTES)

C5 BLADE (1 VOTE)

C6 PRE GROUND (3 VOTES)

C7 PRE GROUND (3 VOTES)

C8 BLADE (2 VOTES)

C9 PRE GROUND (2 VOTES)

DISCUSSION

The data for this specific taste experiment clearly indicates pre-ground was preferred over freshly ground with the blade grinder. Even 3 days after opening the preground, the taste comparisons between the two were vastly different than the previous experiment.
Many of the same tasting notes were obviously carried forward (please reference above) to these cups with the pre-ground being more prominent. Now it should be noted that the overall tasting experience of both coffees was not stellar (no reflection on the roaster!). We attributed this to two factors; 

(1) the pre-ground coffee quickly lost the intensity of the note characteristics with the flavors being muted. We think this is due to the pre-grounds exposure to air which pulled and “dried” the grinds after we broke the seal on the bag from three days earlier. The coffee is 10 days off roast at this time. 

(2) the blade grinds were
anything but worth drinking. We found each cup from the blade grinder was inconsistent, under-extracted and over-extracted at the same time and majoring on the side of tea like.

Of course, when looking at the brewed grinds there was almost half of a bean interwoven with extremely small fines.
We only performed one round with this specific experiment and chose not to perform it again with the paper filter; we had a good idea of what the second round would be like.
.
FINAL THOUGHTS

We really enjoyed performing this experiment. As with any experiment hindsight is 20/20 and there can always be changes or improvements to refine the process. But, here are our thoughts, input, recommendations and just stating the obvious from the experiment. Let us remind you the experiment was based only on answering the specific question: Is it better to pre-grind freshly roasted coffee with a high quality burr grinder for brewing later or grind freshly roasted whole bean coffee with a blade grinder just prior to brewing? We concluded based on taste preference, pre-ground coffee from a quality burr grinder renders a better cup of coffee than whole bean ground just prior to brewing for a pour-over method. The caveat is that both cups of coffee were sub-par compared to freshly ground coffee from a quality burr grinder. A blade grinder is just not an acceptable method for grinding coffee and expecting quality results. The inconsistency of the grind greatly degrades the coffee and does not allow for replicable cups even from a quality roasted coffee.
If someone were to replicate the experiment with a method that required a finer grind, perhaps the blade would fare better. Although pre-ground was the preferred grind method in this pour-over experiment; again sub-par aspects of the cup were evident but preferred over the blade.

Additionally, we concluded that proper storage was paramount especially for the pre-ground. In the end, both options were lousy. If asked by a customer which is better for a pour-over, our response might be, “Purchase only enough coffee for 1 week, get it pre-ground and store it in as optimal conditions as possible.” Customers will ultimately make their decisions based on either quality, cost, convenience, ease or whatever they as individuals deem important. While we do feel a sense of responsibility in helping to educate the consumer, we all know, they will continue to do what they want to do. Perhaps talking to them about a manual hand grinder would be a way to go.

Comments

  1. I would love to see further experiments done such as retrying with an Aeropress or porlex/hario fresh vs higher quality preground. The hand grinders are definitely better than a blade but suffer from inconsistency when increasing the grind size as well.
    A two week comparison would be equally interesting because that is how long some people keep their coffee. Another factor is that some people buy whole beans that come to them 3-7 days off roast but then ask the roaster to grind it for them before taking it home.
    These are just some thoughts I had after reading the experiment. I understand that you have better things to do than humour my flights of fancy.

    Posted by Jason
  2. I vote also for the experiment using an Aeropress with combination of Porlex/Hario fresh hand grinding vs higher quality preground.

    Posted by Martin Velgos
  3. thank you for this post!
    while ago i was thinking about this as i was drinking coffee which was preground two weeks before brewing on Mahlkönig Tanzania and tasted good. i’m not sure if better than coffee ground fresh with my Hario Mini Mill Slim, but i’m gonna try it one day. or you can!
    it would be interesting to see comparasion of hand grinder VS big shop grinder (not the Baratza Preciso as it’s not real professional grinder i think)
    best of luck!

    Posted by Adam Obratil

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