Foeder Pale Sour — Cube 2 / 5 Magics + Muscat

About This Beer

A spinoff of the Foeder Pale Sour I brew. The wort was made on 2026-05-09 with the intent that both cubes go into a 90L ex-whiskey barrel from Dave at Garage Project’s Wild Workshop. The barrel is still inbound, and rather than hold all 46L of wort indefinitely, cube 2 (~20L) has been diverted and pitched onto Paul Fantham’s 5 Magics + muscat grape mixed culture.

Cube 1 (~22L) remains sealed for the barrel. A re-brew of the foeder recipe is planned to replace the diverted volume when the barrel timeline locks in — Jamie Rickard and Paul Fantham have offered to help brew the re-fill.

The Wort

Identical to the parent foeder brew — see Foeder Pale Sour I for the full hot-side process. The grain bill is 66/25/9 Barke Pilsner, Pale Wheat, and rolled oats. Pacific Jade at 27g for 60 min gives ~18 IBU of clean bittering.

Cube 2 was no-chilled from the same kettle run as cube 1 and sat sealed for eight days before being opened for pitch.

Measurements at opening (2026-05-17)

The OG coming in high is worth flagging — useful efficiency-recalibration data for the re-brew that will fill the barrel.

The Culture — 5 Magics, Third Generation, Plus Muscat

Paul evolved the 5 Magics trub through a third-generation brew (the one after Matt and Jamie’s collab was kegged in February). He then captured the Gen-3 trub and combined it with organic muscat grapes — fresh grape skins carrying their own wild microflora (Hanseniaspora, Pichia, possibly Saccharomyces uvarum, plus environmental lactobacillus and pediococcus). The new mixed culture was stepped up over several rounds in DME starters, then split into two jars. Matt received one.

Pitch — 2026-05-17

Cube 2 transferred into a 30L all-rounder in the upstairs room (the upstairs wild workshop), alongside the House Wild Sour ferment that’s been running since February.

Pre-pitch: 2.5 mL of 80% lactic acid (≈ 0.5 tsp) added to the ~20L wort in the fermenter to begin dropping pH from 6.0 before pitching the culture. No probe reading taken after the acid addition — sampling the wort would mean opening it again and losing volume / risking infection.

Pitch: the full ~650 mL of culture (with its own starter at pH 3.8) added to the wort.

Estimating the post-pitch pH

A simple H⁺-conservation mix of 20 L at pH 6.0 with 0.65 L at pH 3.8 gives a calculated pH ≈ 5.22, but this ignores the substantial buffering capacity of wort — in reality the buffer absorbs most of the added acid, pulling the actual blended pH higher (probably 5.7–5.9 pre-acid).

Layering on the 2.5 mL of 80% lactic acid (~0.026 mol of acid into ~20 L of buffered wort) the empirical rule of thumb is roughly 0.3–0.5 units of pH drop per mL per 5 gallons. The realistic post-pitch starting pH is in the 5.0–5.4 range.

This is a calculated estimate, not a measurement — the goal of the calculation was to confirm the lactic addition wasn’t going to overshoot into territory that would inhibit the culture. Actual readings will be taken via sample as fermentation progresses.

Reading Log

At day 19 the gravity is already down to 1.004 from OG 1.056 — roughly 93% apparent attenuation, so the wild Saccharomyces has chewed through nearly all the sugar fast. pH sits at 4.01, comfortably inside the calculated 5.0–5.4 post-pitch estimate’s downward trajectory and right where a young wild sour should be before the slow acid producers do their work.

The tasting character is the more interesting story. Paul deliberately worked to suppress the lactobacillus in favour of cultivating a good wild Sacch, and that intent is showing: clean Belgian-leaning esters and spice/clove, a subtle sourness rather than an aggressive one, and none of the sweaty-funk or horse-blanket notes that can dominate an early wild ferment. As Paul put it — sourness is the easy part to create; the complexity of a wild Sacch and Brett are the characters that are harder to domesticate. The faint Brett hint and the yeast still rafting (no pellicle yet) both say this is still early.

What’s Next

Sitting in the 30L all-rounder in the upstairs wild workshop. With the first sample in (day 19, SG 1.004 / pH 4.01) the primary Sacch work is essentially done. Plans:

1. Leave it undisturbed and sample again in ~a month (early July), recording SG and pH.
2. Watch for a pellicle forming and track whether the faint Brett character builds — Brett complexity typically takes 6 weeks to 3 months to really show, so the interesting flavour development is still ahead.
3. Subsequent samples every 4–6 weeks, recording SG and pH.
4. Compare progression against the House Wild Sour sitting alongside it — same room, same temperature, but very different cultures and starting gravity (1.056 vs 1.048).

Lineage

• Parent recipe + sibling cube: Foeder Pale Sour I — cube 1 still sealed for the barrel
• Source of the 5 Magics culture: Wild Sour — Paul Fantham Collab — Gen-2 brew that fed Paul’s later evolutions
• Co-located ferment in the upstairs wild workshop: House Wild Sour