BJCP National · Lesson 4 · Recipe question (R0)

R0: reconstruct a recipe, don't memorise twelve

The exam names ONE style and asks for a plausible all-grain recipe that hits it. You do not carry twelve recipes in your head. You carry four grain bases, three hop loads, one tiny OG sum, and the per-style yeast/water. Then you assemble on the page.

Aim. R0 is the only question where parameters are scored (since V.2023). Own the four-part rubric, be able to write the OG maths from memory, and reconstruct any of the twelve pool styles into grain + hops + yeast + process in about ten minutes. The twelve model recipes at the bottom are your self-check key – you reproduce, you never memorise.

Compress: the one idea

A recipe is three near-independent choices: (1) a grain archetype (base malt + colour/specialty), (2) a hop load (bitterness/aroma level), (3) yeast + water (fermentation character). Learn 4 archetypes + 3 hop loads, keep yeast/water per style, and you can build all twelve. Compressed from the R0 families model, synthesised from 2021 Guidelines Characteristic Ingredients across the twelve R0 styles.

The trap that wastes recipe answers is treating each style as a unique memory item. It is not. Festbier is a pale Märzen. Double IPA is a bigger American IPA. Czech Premium Pale is German Pils with three swaps. Learn one, flip one knob.

The four-part rubric (this is how R0 is graded)

Write your answer in these four blocks, in this order, and you cover every point the grader counts.

Part	Weight	What to write
Style description	15%	One line from the Overall Impression (the S0 muscle pays off here).
Target parameters	15%	Quote the style's OG / FG / IBU / SRM / ABV range and pick a value inside each. This is the one place params score.
Ingredients	40%	Grain bill in kg + why each malt (colour + character), the yeast, the hops (variety + load), and show the OG maths.
Procedure	30%	Mash type, boil, fermentation, packaging – matched to the style.

Ingredients + procedure are 70% of the mark. Do not spend all your time on the parameter table.

The maths you must be able to write from memory

Only three formulas, and they all hang off one sum. Design in metric (kg, L, °P, PKL) – your home units – and only report OG/FG in SG because the Guidelines use SG.

OG points = Σ(kg × PKL) × efficiency ÷ litres (the one you SHOW)
FG points = OG points × (1 − attenuation)
ABV% = (OG − FG) × 131.25 Print-verified Palmer, metric edition (PKL = points per kg per litre). See the recipe-calculation backend.

SRM and IBU – skip the ugly formulas. The Study Guide recipe rubric (verbatim) accepts bitterness "in IBUs or HBUs" and colour as "SRM or a textual description". So you never touch the Morey colour curve or the Tinseth IBU-utilisation formula.

Bitterness: two units, two jobs – do not convert them. Quote and TARGET in IBU (the Guidelines' scale, the one you can actually taste – e.g. German Pils 22–40, pick 35). Then EXPRESS the hop bill in HBU = grams × %alpha (e.g. 50 g Hallertau at 4% = 200 HBU). HBU is just the alpha-acid load you add, not a perceived-bitterness scale – the Study Guide calls it "potential bitterness". So do not try to feel 200 HBU, and do not equate it to the 35 IBU target; the rubric accepts either unit, so target in IBU and tally hops in HBU. Never the utilisation monster IBU = 7489 × (W×A×U)/V.

How do you know it is right? Check the GRAMS, not the HBU. There is no single correct hop number, so your confidence comes from the hop weight being sane for the style – anchor to the model recipes below. Per 20 L of the appropriate variety: LOW ≈ 15–30 g (Weissbier, Märzen, Festbier, Doppelbock) · MODERATE ≈ 35–55 g (Tripel ~35, Pils, Czech, Bitter, Porter, Stout) · HIGH ≈ 120–200 g + big late/dry (IPA, DIPA). If your grams sit in the style's tier, the bill is right – the HBU figure itself never has to mean anything.

HBU counts BOIL hops only. Bitterness needs isomerisation in the boil, so only boil additions count – and the bittering charge (60 min) drives it. Flame-out and dry (cold) hops add little or no isomerised bitterness – a hot whirlpool/flame-out steep can contribute some IBU, and dry hops a slight perceived bitterness (humulinones/polyphenols), but for a recipe answer treat them as aroma and keep them out of the HBU tally. Watch the mismatch on hoppy styles: the grams tiers above are the total hop weight, but for an IPA most of that 120–200 g is late/dry aroma – the HBU is computed only on the ~30–40 g high-alpha bittering charge.

Colour = quote or describe. Quote the SRM range and pick a value, justified by grain: pale/Pilsner ≈ 3 · + Munich/crystal ≈ 8–12 (amber) · + chocolate ≈ 20–30 (brown/porter) · + roasted barley ≈ 30–40 (black/stout). A textual description ("deep amber") is explicitly allowed.

The 40% "explain how the quantities were calculated" is mainly the grain bill → OG sum; for hops, the one-line HBU = g × %alpha covers it.

PKL you actually need (max yield): Pilsner/lager 309, Munich 300, wheat 309, Vienna ~292, crystal-15 292, crystal-40/60/75 ~284, chocolate 284, roasted barley 300, flaked barley ~267, table sugar ~384, dextrose ~350. Default 75% efficiency, declare it, compute everything on it. Bitterness: state a target IBU from the range + the hop bill (variety, grams, %AA, timing); skip utilisation – HBU = g × %AA is enough.

Worked once, so you can do it cold – German Pils, 20 L, 75% eff.

4.15 kg Pilsner (309 PKL). OG = 309 × 4.15 × 0.75 ÷ 20 = 48 pts → 1.048.
FG at 80% attenuation = 48 × 0.20 = 9.6 → 1.010.
ABV = (1.048 − 1.010) × 131.25 = 5.0%.
SRM: all pale Pilsner malt → very pale, ~3 (quoted inside the 5D range 2–4; no calculation).

The OG ruler + FG rule (reconstruct any target in your head)

Everything on 75% efficiency, 20 L, pale base (~309 PKL). The one honest tool is a linear ruler; the "tiers" are just handy clumps on it:

OG points ≈ 11.6 × kg of base – so +0.5 kg ≈ +6 points. Aim for the low end of each style's range so styles share one weight – twelve styles collapse to four grain weights:

kg base	OG	Styles (aim low, share the weight)
~3.5	~1.040	Irish Stout (the one low outlier)
~4.3	~1.050	German Pils, Czech, Weissbier, Strong Bitter, American Porter
~4.8	~1.056	Festbier, Märzen, American IPA
~6.5	~1.075	Doppelbock, Double IPA, Belgian Tripel

Strong Bitter (1.048–1.060) and American Porter (1.050–1.070) drop to their floor ~1.050 and join the standard weight – within a group you only change the specialty malt, hops and yeast, not the base weight. Caveat found in verification: aim low unless it breaks the ABV floor. Festbier (ABV min 5.8%) and Märzen (min 5.6%) cannot bottom out, so they hold ~1.056–1.057, not lower.

FG = OG × (1 − attenuation), not a fixed 1.010. Two multipliers plus one exception land every FG range (Codex-checked, 12/12):

Band	FG ≈ OG ×	Styles
Dry (~80%)	0.20	German Pils, Festbier, American IPA, Double IPA
Malty (~75%)	0.25	Czech, Märzen, Doppelbock, Strong Bitter, American Porter, Irish Stout, Weissbier
Belgian Tripel	0.14	sugar ferments it bone-dry (~86%)

Worked: Doppelbock 1.075 × 0.25 → FG 1.019; Tripel 1.080 × 0.14 → FG 1.011. Near-identical OG, very different finish – that is exactly why FG cannot be one fixed number.

IBU → bands: ~12 (Weissbier) · ~20 low/malty (Märzen, Festbier, Doppelbock) · ~30–40 moderate (Pils, Czech, Tripel, Strong Bitter, Porter, Stout) · 60–90 high (American IPA, Double IPA). State a target from the range; do not compute it.

The four grain archetypes

Base	Grain template	Covers
A · Pale base	Mostly Pilsner/pale 2-row. + sugar to dry out/boost ABV (Tripel, DIPA); + a little Vienna/Munich for malt (Festbier).	German Pils, Czech Premium Pale, Festbier, Belgian Tripel, American IPA, Double IPA
B · Malty amber lager	Munich (+Vienna) backbone over Pils; small % dark malt for colour only (Doppelbock). Decoction deepens malt.	Märzen, Doppelbock
C · Crystal/roast ale	Pale ale malt + crystal; slide the dark end: none → Bitter, chocolate → Porter, roasted barley → Stout.	Strong Bitter, American Porter, Irish Stout
D · Wheat	≥50% malted wheat + Pilsner. The style IS the yeast.	Weissbier

Base A shares GRAIN ONLY, not fermentation. Half of family A is ale. Split it before writing the 30% procedure:

Cold lager + diacetyl rest + lagering: German Pils, Czech Premium Pale, Festbier.
Warm ale, no diacetyl rest, no lager phase: American IPA, Double IPA (clean US yeast), Belgian Tripel (expressive Belgian yeast).

Never write "lager, diacetyl rest" for a Tripel or an IPA.

The three hop loads

Low (balance only, ~8–26 IBU): Weissbier 8–15, Märzen 18–24, Festbier 18–25, Doppelbock 16–26. Single bittering charge.
Moderate (bittering + modest late, ~20–50): German Pils 22–40, Czech 30–45 (Saaz late), Tripel 20–40, Strong Bitter 30–50, American Porter 25–50, Irish Stout 25–45.
High (bittering + big late + dry hop, 40–100): American IPA 40–70, Double IPA 60–100.

Memory hooks – learn one, flip one knob

Festbier = pale Märzen. Same strength (OG ~1.056), same low ~20 IBU, same clean German lager yeast. Only the malt colour changes: Festbier Pils-forward/pale (SRM 4–6), Märzen Munich-forward/amber (SRM 8–17).
Czech Premium Pale = German Pils + 3 swaps: Saaz (not German noble), soft low-sulfate water (not high-sulfate), fuller/sweeter finish (FG ~1.014). Same grain, same OG.
Double IPA = a bigger American IPA: same pale base + clean US yeast + US hop character, scaled up (more grain + sugar + hops).
Porter vs Stout = which dark grain leads: American Porter is chocolate-led; Irish Stout is roasted-barley-led. Strong Bitter is the same pale+crystal backbone with no roast at all.

On the exam you draw Festbier. You already know Märzen cold. What single thing do you change?

Say it out loud in full sentences before you reveal. Half-answers count as misses.

Drop the Munich, go Pils-forward (paler)

Festbier is a pale Märzen: same OG/IBU/yeast, just Pils-forward so SRM falls to 4-6.

The twelve model recipes – your self-check answer key

Do not memorise these. Draw a style, write your own recipe on paper timed, then check it here. Every recipe is 20 L at 75% efficiency, every parameter lands inside the 2021 range, and the arithmetic was verified two independent ways. Grain is kg; the OG/FG/ABV/SRM shown are what the bill actually produces.

Style (cat)	Base	Grain bill (20 L, 75%)	OG / FG / ABV / SRM	Hops → IBU	Yeast / water
German Pils 5D	A	4.15 Pilsner	1.048 / 1.010 / 5.0% / 3	~45 g German noble (Hallertau/Tettnang), 60 min + late → 35	Clean German lager; high-sulfate
Czech Prem. Pale 3B	A	4.30 Czech Pilsner	1.050 / 1.014 / 4.7% / 4	~55 g Saaz, 60 min + late → 38	Czech lager; soft (low sulfate+carbonate); decoction
Festbier 4B	A→B	3.85 Pilsner + 1.00 Munich	1.056 / 1.011 / 5.9% / 6	~30 g German noble, 60 min → 22	German lager; soft
Belgian Tripel 26C	A	5.70 Pilsner + 0.30 Munich + 0.80 sugar	1.081 / 1.011 / 9.2% / 4.8	~35 g Continental noble (Styrian/Saaz), 60 min → 30	Expressive Belgian ale; soft; warm ferment
American IPA 21A	A	4.55 pale + 0.30 crystal-40	1.056 / 1.011 / 5.9% / 6	~120 g US (Cascade/Centennial/Simcoe): small 60 min + big late + dry hop → 60	Clean/lightly fruity US ale; sulfate-forward
Double IPA 22A	A	5.80 pale + 0.40 sugar + 0.30 crystal-40	1.076 / 1.012 / 8.3% / 7	~200 g US/New World: modest 60 min + huge late + big dry hop → 90	Neutral US ale; sulfate-forward
Märzen 6A	B	3.50 Munich + 1.50 Pilsner	1.057 / 1.012 / 5.9% / 10	~25 g German noble, 60 min → 22	Clean German lager; decoction
Doppelbock 9A	B	5.00 Munich + 1.50 Pilsner + 0.10 chocolate (colour)	1.075 / 1.018 / 7.5% / 18	~30 g German noble, 60 min → 22	Clean German lager; decoction; long lager
Strong Bitter 11C	C	3.90 pale ale + 0.45 crystal-60	1.050 / 1.012 / 4.9% / 9	~50 g English (EKG/Fuggle), 60 min + late → 40	Characterful British ale; Burton sulfate optional
American Porter 20A	C	3.55 pale + 0.35 crystal-60 + 0.45 chocolate	1.050 / 1.013 / 4.8% / 29	~55 g US bittering (+ US/UK finish), 60 min + late → 35	Clean US or English ale
Irish Stout 15B	C	2.85 pale + 0.40 flaked barley + 0.50 roasted barley	1.043 / 1.010 / 4.3% / 26	~50 g English (EKG/Target), 60 min → 40	Irish ale
Weissbier 10A	D	2.10 wheat + 2.10 Pilsner	1.049 / 1.012 / 4.9% / 3	~15 g German noble, 60 min → 12	Weizen yeast, cool ferment (banana/clove); decoction

Procedure by base (the 30%): mash – decoction for B and D (malty lager, wheat), single infusion fine for A and C; boil – long, open, ≥60 min if Pils-heavy (drives off DMS); ferment – lagers cool + diacetyl rest (15–18 °C) then lager cold, ales warmer with no lager phase, let Weizen/Belgian yeast express; then package and carbonate to style.

Keep the procedure minimal – write only the mandatory chain. One template covers every style; drop every optional flourish so there is less to learn and less to get wrong.

Always: single-infusion mash ~66 °C → 60-min boil → ferment (ale warm ~18–20 °C / lager cool ~10 °C + diacetyl rest) → package + carbonate to style.

Skip (nice-to-have, not required, so do not write them as steps): whirlpool / hop stand, first-wort hopping, kettle finings, step mashes.
Decoction is the one exception: do not actually do it, but for Märzen / Doppelbock / Weissbier you must still describe what it is (see the box below) – that is where the knowledge points are.
Do NOT drop for IPA / Double IPA: the big late addition + dry hop is not an optional flourish there – hop aroma is what defines those styles, so a grader expects it. Everywhere else, no dry hop.

Mash technique on R0 – the rule to write. You can brew any of the twelve as a single-infusion mash with modern well-modified malt, and the OG maths is identical either way (mash technique does not change the OG number – only efficiency and volume do). But when the style is traditionally decocted – bases B (Märzen, Doppelbock) and D (Weissbier) – name decoction and describe it, because it is flavour-relevant, not just history: boiling a fraction of the mash builds the melanoidins that give these styles their rich, bready-toasty malt depth.

Decoction, to memorise: pull off ~1/3 of the mash (the thick portion), give it a brief saccharification rest, boil it 15–30 min, then stir it back into the main mash – which steps the whole mash up to the next rest temperature. Boiling ruptures the starch granules, breaks the protein matrix of undermodified malt, and forms melanoidins (rich malty depth). Repeat up to 3× (single / double / triple decoction). CON: the most time-, energy- and labour-intensive method.

Model line: "Single-infusion ~66 °C is adequate with modern malt; traditionally a decoction mash is used to develop the melanoidin-rich malt depth characteristic of the style."

You draw Belgian Tripel (OG 1.075–1.085) but it must finish dry and not heavy. Which grain move gets you there?

Say it out loud in full sentences before you reveal. Half-answers count as misses.

Pilsner base + ~0.8 kg sugar

Sugar adds fermentable extract that ferments out fully, lifting ABV while drying and lightening the body - the classic Tripel move.

Feynman teach-back

Cover the screen. Out loud, in English, answer a full R0 for American Porter in four blocks: (1) one-line style description, (2) target params picked inside the range, (3) grain bill in kg with the OG sum shown + why each malt + hops + yeast, (4) procedure. Then reveal and check against the key.

Style (15%): A substantial, malty dark ale with a complex, roasty character and restrained bitterness; chocolate-led rather than the sharp roasted-barley edge of a stout.

Params (15%): OG 1.050 (range 1.050–1.070, aim the floor), FG 1.013 (1.012–1.018), IBU 35 (25–50), SRM 29 (22–40), ABV 4.9% (4.8–6.5%).

Ingredients (40%): 3.55 kg pale ale malt (base, dry body), 0.35 kg crystal-60 (caramel depth), 0.45 kg chocolate malt (the chocolate-led roast + colour). OG = (309×3.55 + 284×0.35 + 284×0.45) × 0.75 ÷ 20 = 50 pts → 1.050. FG at 74% att → 1.013; ABV = (1.050−1.013)×131.25 = 4.9%. ~55 g US bittering hops at 60 min for ~35 IBU. Clean US or English ale yeast.

Procedure (30%): single-infusion mash ~66 °C, 60-min boil, ferment warm (18–20 °C) with no lager phase, condition and carbonate to medium.

Run: today's scoring artifact. Add this R0 checklist line to your drill scoresheet:

"Four blocks present? Style line · params inside range · grain bill + OG sum shown + why-each-malt + yeast + hops · procedure matched to base (lager vs ale). Missing the OG sum or the procedure = the two most-dropped chunks."

Trap watch. Parameters are scored only here – but grain, hops, yeast and procedure are 70% of R0. A perfect parameter table with a vague grain bill and no maths scores worse than a rough table with a fully-worked, well-justified recipe.

Primary source

Every parameter in the twelve recipes is quoted from the BJCP 2021 Style Guidelines Vital Statistics (verified per style). The formulas and PKL values are print-verified against the physical Polish Palmer (Jak warzyć piwo, Tables 15.2 / 18.4 / A.2 / 9.1). Grain bills are computed to hit each style's OG, then checked two independent ways.