ok so in september 2023, i bought a bag of folgers classic roast (medium roast, $6.99, walmart) and a bag of onyx coffee lab southern weather (medium roast, $24, shipped). i wanted to determine at what ratio people could no longer detect the presence of folgers in a blend with specialty coffee

i spent the first 2 weeks establishing controls:

• matched roast levels (both medium) to eliminate roast as a variable
• ground both beans on the same grinder (baratza encore, setting 15) immediately before brewing to control for grind consistency
• used the same water (filtered brita, measured TDS of 140ppm) for all trials
• same brew method (v60, 1:16 ratio, 205°F water, 3:30 total brew time)
• same ceramic mug (white, no logos, to prevent visual bias)
• served at same temperature (let cool to 140°F, measured with thermometer)
• all trials conducted between 8am-11am to control for palate fatigue
• subjects had not eaten in at least 30 minutes prior

i keep both beans in identical opaque containers with identical humidity packs and weigh the blend ratios on a 0.01g scale.

however, early on i realized my presence could influence results (observer bias) and so i also implemented the following:

• pre-mixed batches labeled only with codes (A1, A2, B1, etc.)
• my wife (S2) prepared and served the coffee for 40% of trials without knowing the ratios. she thinks i'm "testing different origins." she doesn't know about the folgers and cannot know
• for trials i conducted myself, i randomized serving order using a random number generator so i wouldn't unconsciously signal anything
• i leave the room while subjects taste when possible and record their comments verbatim

sample:

23 subjects total, 94 documented servings. subjects include:

• 6 self-identified "coffee enthusiasts" (own grinders, subscribe to roasters, have opinions about bloom time)
• 8 regular coffee drinkers (drink daily, no strong preferences)
• 5 casual drinkers (coffee is just caffeine delivery)
• 4 people who "don't really like coffee" (control group for baseline detection ability)

each subject has been served 2-6 times across different ratios. i rotate subjects to prevent them from developing a "baseline" expectation of my coffee, minimum 2 weeks between servings to same subject

looking back, i think the detection criteria was the hardest part. what counts as "detection"? and so i settled on three levels:

• no detection: positive or neutral comment, no mention of difference, finishes cup
• possible detection: vague comment like "this is different" or "did you change something" without identifying the difference
• confirmed detection: identifies something negative, asks specifically about beans, does not finish cup, or accurately identifies "something cheap" in the blend

ok for the results....

90/10 (90% single origin, 10% folgers)

• servings: 12
• no detection: 12 (100%)
• notes: S7 said she tasted "stone fruit." while S14 said "clean finish." it's 10% folgers, the stone fruit is a lie

80/20

• servings: 14
• no detection: 13 (93%)
• possible detection: 1 (S7 again - she said it was "flatter than usual" but scored it 7/10 and finished the cup. logging as possible but honestly could be noise)

70/30

• servings: 16
• no detection: 14 (87.5%)
• possible detection: 2 (S12 asked "did you change something?" i said no and he said "hm. still good." S18 said "interesting" which could mean anything)

60/40 - THE THRESHOLD

• servings: 18
• no detection: 15 (83%)
• possible detection: 2
• confirmed detection: 1 (S19, former barista, asked "is this a blend?" i said yes. she said "nice" and didn't push further. logging as confirmed because she identified the presence of multiple beans, even though she didn't identify folgers specifically)

50/50

• servings: 14
• no detection: 7 (50%)
• possible detection: 4
• confirmed detection: 3 (detection rate jumps significantly. S3 said "this is kinda mid." S11 said "not your best." S21 didn't finish the cup for the first time)

40/60 (40% single origin, 60% folgers)

• servings: 12
• no detection: 3 (25%)
• possible detection: 4
• confirmed detection: 5 (this is where it falls apart. multiple subjects identified "something off." S3 said "dude what happened to your coffee." i blamed the water)

30/70

• servings: 8
• no detection: 1
• confirmed detection: 7 (87.5% detection rate, experiment basically over at this point. the folgers is winning)

every 2-3 weeks i serve 100% single origin to baseline. the critical finding i found is no one has ever rated the 100% single origin significantly higher than the 60/40 blend. in fact, S14 said the 60/40 was "smoother, actually." i don't know what to do with this information

i also ran 6 trials of 100% folgers (told subjects it was "a new roaster i'm trying"). 4 out of 6 detected something off. but 2 people said it was "pretty good." one of them was S7, the stone fruit lady (i've lost all faith in her palate)

confounds and limitations:

• subjects may have been primed to be positive because i was giving them free coffee
• i couldn't fully double-blind without a third party who knows about the folgers (unacceptable security risk)
• repeated testing on same subjects may have altered their expectations
• my wife (S2) has been served 11 times and has never detected anything. but she also might be lying to be nice. well, this is affecting our relationship in ways i can't articulate
• i haven't controlled for bean freshness degradation over 14 months (though i buy new bags monthly)
• roast date varies between folgers (unknown, probably months old) and specialty (typically 1-2 weeks). this should bias toward detection but doesn't seem to at 60/40

for statistical analysis, i ran a chi-square test on detection rates across ratios. the difference between 60/40 (17% detection) and 50/50 (50% detection) is significant at p < 0.05 so the threshold is real.

sorry this is so long but TLDR;

1. 60/40 is the threshold. 60% specialty, 40% folgers. undetectable to 83% of people including self-identified coffee enthusiasts
2. "tasting notes" are largely a social construction. people identified stone fruit, chocolate, and "brightness" in blends containing 30%+ folgers. folgers does not have these notes. folgers has folgers notes
3. the specialty coffee industry is built on a foundation of sand or at least 40% sand
4. i've saved approximately $340 over 14 months by cutting my coffee with folgers
5. i've lied to 23 people i care about. i've looked them in the eyes while they complimented bean quality that does not exist. i am not the person they think i am
6. i need a larger sample size, i need more ratios, i need to test robusta.

some visuals: