Brandywine Coffee Roasters

Stellar Collisions Next Generation - Peach Co-ferment Blend

colombia medium-light roast anaerobic_washed caturra

Anaerobic washed processing is rare in Colombian specialty coffee — the vast majority is standard washed. The distinction matters because the fermentation environment before depulping fundamentally changes what compounds end up in the bean. In standard washed processing, cherries are depulped first, then the remaining mucilage ferments aerobically in open tanks for 12 to 72 hours. Anaerobic washed reverses the oxygen exposure: whole or depulped cherries ferment in sealed tanks before washing. Without oxygen, microbial activity shifts from acetic acid-producing pathways toward lactic acid bacteria and volatile ester production — ethyl butyrate and other fruit-adjacent compounds that don't form in open-air fermentation. The result is a cup that retains the clean structure of washed processing while carrying a volatile profile that doesn't belong to standard washed Colombia. The peach co-ferment adds fruit substrate to that sealed environment, further tuning fermentation chemistry toward specific ester profiles. The peach character is chemically real — not the bean's terroir, but fermentation-derived compounds introduced through the substrate and fixed in the bean during drying. Medium-light roasting sits between the acid-forward light and the deeper Maillard territory of medium. At 1,900 meters, this bean has accumulated enough solubles to support that intermediate development without going thin — altitude explains about 25% of extraction yield variation, and the high altitude here provides the soluble density to absorb medium-light's slightly longer development time without losing the fermentation-derived volatiles to heat. As a blend, component lots from two regions require a parameter compromise rather than optimization for a single terroir.

Chemex 6-Cup 90/100

Grind: 535μm Temp: 91°C Ratio: 1:14.8-1:16.8 Time: 3:30-4:30

The Chemex earns the top score for Stellar Collisions because its thick paper filter does a specific job with anaerobic washed Colombian Caturra: it strips the heavier oils that anaerobic fermentation produces while allowing the fruit character to come through cleanly — the peach co-ferment character — fully accessible in the brew. The peach character develops during the sealed co-fermentation process, and the resulting fruit aromatics pass through paper filters cleanly. At 1,900 meters, this Caturra accumulates enough solubles to support Chemex's slower drawdown without going thin — at near-2,000 meters, the soluble density is high enough to extract evenly through thick paper at 91°C. The 91°C temperature (3°C below default, adjusted for medium-light roast and anaerobic processing) protects the delicate fermentation aromatics from dissipating under higher heat.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. At 1,900m, Caturra has high acid density from slower cherry maturation — if extraction stalls in the acid zone, the peach co-ferment reads as sharp rather than fruity. More surface area pushes past the CGA zone into the caramelization compounds.

thin: Increase dose by 1g or reduce water by 15g. Despite 1,900m altitude, the anaerobic washed process and medium-light roast both suppress body relative to heavier-processed alternatives. If the cup is watery, tighten the ratio — Chemex's slow drawdown already maximizes extraction, so dose is the next lever.

Hario V60-02 89/100

Grind: 485μm Temp: 91°C Ratio: 1:14.8-1:16.8 Time: 2:30-3:30

Stellar Collisions on the V60 requires the grind landing at 485μm — 15μm finer than the default. The medium-light roast pulls the grind finer for solubility, while the anaerobic washed processing backs it off slightly because the processing-derived compounds extract more readily. The practical effect is that the grind needs to balance two competing forces: dense, less-soluble beans that want finer grinding, and fermentation chemistry that extracts quickly and risks over-extraction if pushed too hard. As a blend of two different regional lots, a single grind setting has to work for beans with somewhat different extraction kinetics. The 91°C temperature — well below the V60 default — protects the peach co-ferment aromatics, which are introduced through the fermentation process rather than developed from the bean's own terroir, and are as heat-fragile as any other processing-derived volatile.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. The Caturra at 1,900m carries significant citric and malic acids from altitude-concentrated cherry development — if you're tasting sharp citrus rather than stone fruit, extraction hasn't reached the sweet phase. Finer grind at 91°C moves through the CGA zone faster.

thin: Increase dose by 1g or reduce water by 15g. Anaerobic washed with no fruit substrate contact means less body contribution than a natural would provide — the V60's paper filter also strips oils. If the peach character is clean but the cup feels light, pull the ratio tighter before adjusting grind.

Kalita Wave 185 88/100

Grind: 515μm Temp: 91°C Ratio: 1:15.8-1:17.8 Time: 3:00-4:00

The Kalita Wave's flat-bottom basket is particularly relevant for Stellar Collisions as a blend: flat-bottom drippers produce more uniform extraction than conical brewers because water residence time is equalized across the bed rather than concentrated at the center exit point. For a blend of two regional lots, that uniformity matters — beans from two different growing zones will have slightly different extraction kinetics, and the Wave's design minimizes the risk of one component over-extracting while the other under-extracts. The recipe sits at 515μm and 91°C, carrying the same -3°C temperature reduction and -15μm net grind adjustment as the other pour-overs. The Caturra variety has dwarf stature and grows at high density in Colombian conditions — its compact cellular structure produces relatively uniform particle sizes when ground, which the Wave's flat bed exploits effectively.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. Blend components from different altitudes can extract unevenly even in the Wave's uniform bed — if sourness persists, a slightly finer grind increases total extraction across both components simultaneously, pushing past the acid-dominant zone.

thin: Increase dose by 1g or reduce water by 15g. Anaerobic washed Colombian without oil contribution from natural processing means the Wave produces a clean, bright cup — but clean can read as thin if the ratio isn't tight enough. Tighten dose before reaching for the grind.

AeroPress 84/100

Grind: 385μm Temp: 82°C Ratio: 1:11.8-1:13.8 Time: 1:00-2:00

AeroPress runs at 82°C for Stellar Collisions — 9°C below the pour-over recipes, matching the same low-temperature profile as Das Almas. The combination of low temperature, short brew time (1–2 minutes), and 385μm fine grind creates a distinctive extraction environment for the peach co-ferment aromatics: the low temperature reduces volatile loss during brewing, while the fine grind compensates for the reduced extraction kinetics at lower heat. The paper filter clears the oils, emphasizing the clean, fruit-forward character that the anaerobic washed process produces — washed structure (no oil contribution from fruit contact) plus anaerobic volatile production means this bean is ideally suited to paper filtration that preserves fruit clarity. The 1:11.8–13.8 ratio is on the tighter side for AeroPress, concentrating the peach notes relative to the base acidity.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. At 82°C with a 1–2 minute window, Caturra's high-altitude acid density extracts fast — if the peach reads as sharp citric rather than stone fruit, the brew terminated in the acid zone. Finer grind increases extraction rate within the short press time.

thin: Increase dose by 1g or reduce water by 15g. Low-temperature AeroPress extracts less TDS than pour-over at higher temperatures — for a washed-structure anaerobic with no oil contribution, the cup can be clean but light. Tighten the ratio before adjusting grind when thin is the issue.

Clever Dripper 84/100

Grind: 515μm Temp: 91°C Ratio: 1:14.8-1:16.8 Time: 3:00-4:00

The Clever Dripper's immersion environment interacts with Stellar Collisions' peach co-ferment aromatics differently than flow-through pour-overs. In the Clever's 3–4 minute immersion, the processing-derived delicate aromatics dissolve into the water rapidly in the first phase, then extraction decelerates as the water-to-coffee extraction rate narrows. This natural deceleration is protective for a bean where the most interesting compounds are the most soluble — the peach aromatics extract early, and the immersion's self-limiting kinetics reduce the risk of pushing into the slower-extracting bitter compounds in the final minutes. The recipe runs at 515μm and 91°C, matching the Wave's parameters. Paper filtration at drawdown ensures the oil-stripping that the anaerobic washed process requires to present clean fruit over structured bitterness.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. Immersion in the Clever can equilibrate around the acid compounds if extraction ceiling is low — finer grind raises the maximum achievable extraction before equilibrium is reached, pushing the cup out of the CGA-dominant zone.

thin: Increase dose by 1g or reduce water by 15g. The Clever's paper filter and immersion produce a clean cup but less body than a metal filter method — for this washed-structure anaerobic, thin is the likely failure mode. Dose is the more reliable adjustment than grind for TDS in immersion brewing.

Espresso 72/100

Grind: 235μm Temp: 90°C Ratio: 1:0.8-1:2.8 Time: 0:25-0:30

Espresso amplifies every dimension of Stellar Collisions — at 72/100, the match score reflects the challenge of concentrating a peach co-ferment blend under pressure. The 9-bar extraction compresses all extraction phases, which means the peach fruit compounds and the base Colombian Caturra acidity from 1,900 meters reach your palate simultaneously and at high intensity. Temperature is 90°C (the same -3°C composite delta as other methods, rounded differently at espresso's tighter tolerance). The grind at 235μm is 5μm finer than Das Almas espresso, matching the -15μm net modifier from Caturra's slightly larger grind adjustment. The sour troubleshooting gets the highest score here (55/100) because 1,900m Colombian Caturra with high acid density under-extracts easily as espresso — the pressure window for extracting through the initial bright acids into the caramel-peach zone is narrow.

Troubleshooting

sour: Grind finer by ~10μm and raise temp by 1°C. At 1,900m, Caturra's acid density is high — under 9 bars the citric and fermentation acids extract first and dominate if the puck resistance is too low. The peach character requires extraction depth past that acid-forward zone. Use 10μm increments — espresso is sensitive.

bitter: Grind coarser by ~10μm and drop temp by 1°C. When the peach disappears and the finish turns dry and harsh, pressure has extracted through the sweet zone into dry distillates. The anaerobic washed process leaves fewer buffering compounds than natural processing — over-extraction shows up faster.

Moka Pot 63/100

Grind: 335μm Temp: 97°C Ratio: 1:8.8-1:10.8 Time: 4:00-5:00

Moka Pot at 63/100 for Stellar Collisions reflects the temperature risk: moka pot brewing at high heat drives off the volatile peach co-ferment aromatics before they can concentrate into the brew. The processing-derived peach character — produced by yeast metabolizing added peach substrate in sealed tanks — sits in the same compound class as other delicate aromatics from anaerobic processing. At 97°C starting temperature (pre-boiled water), those esters are the first aromatics to vaporize during the several-minute extraction. The recipe runs at 335μm and 1:8.8–10.8, similar to Das Almas moka parameters but 5μm finer to compensate for Caturra's slightly higher density at 1,900m versus Das Almas's 975m Catuai. What the moka delivers here is concentrated Colombian body and acidity — the peach co-ferment becomes a mild top note rather than the defining character.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. Caturra's high acidity at 1,900m is concentrated further under moka pressure — if the cup is sharp rather than structured, grind finer to push extraction past the CGA-dominant phase. Without tamping, fine moka grind distributes extraction pressure more evenly across the basket.

strong: Decrease dose by 1g or increase water by 15g. The 1:8.8 ratio is already concentrated — Colombian Caturra under moka pressure produces intense TDS quickly. If the body is overwhelming the fruit structure, the ratio is the primary adjustment before reaching for grind.

French Press 60/100

Grind: 985μm Temp: 93°C Ratio: 1:13.8-1:15.8 Time: 4:00-8:00

French Press at 60/100 for Stellar Collisions means the bean can be brewed this way, but with a trade-off: the metal mesh passes the heavier fermentation-associated oils and larger lipid compounds into the cup. Anaerobic washed processing produces different flavor characteristics than standard washed — the sealed fermentation environment generates byproducts beyond just the delicate aromatics, and without paper filtration, these heavier compounds create a coating on the palate. The peach co-ferment character still extracts — the esters are water-soluble — but the oil layer changes how they're perceived. The recipe at 985μm and 93°C is calibrated for immersion with the metal mesh: coarser grind limits extraction rate at the higher French press temperature, and the slightly elevated temperature versus Clever compensates for the coarser particle size.

Troubleshooting

sour: Grind finer by ~22μm and raise temp by 1°C. Coarse French press grind can underextract Caturra's high-altitude acid density — if the peach reads as sharp citric rather than stone fruit, the extraction stalled before reaching the caramel and sweetness zone. Grind finer and wait the full 4–8 minutes before pressing.

strong: Decrease dose by 1g or increase water by 15g. Metal mesh lets fines through, which continue extracting after pressing — Colombian Caturra at 1,900m produces significant fine-extractable solids. If the cup is intensely strong, loosen the ratio and pour immediately after pressing rather than letting it sit.

Cold Brew Flash Brew Recommended

Cold brew is not recommended for this bean. At near-freezing temperatures, cold water cannot extract the complex acids, delicate aromatics, and bright fruit compounds that define a light-roasted coffee — they remain locked in the cell matrix. For a cold version of this coffee, use flash brew: brew a concentrated pour-over (V60 or Chemex at 60% of the normal water volume) directly over ice in the server. The hot water extracts the full flavor spectrum, and the rapid ice cooling locks in volatiles that would otherwise evaporate during a slow cool-down.