BJCP National · Lesson 17 · Technical pool (P0) · 7 days to exam
This is the most mechanical question in the whole technical pool, and it is the one where a checklist beats understanding. The stem gives you the structure outright: define the technique, then say what it does to the finished beer. Three techniques, two slots apiece. Six things. Miss one slot and you have left a sixth of the question on the table without ever knowing it.
raw/study-guide/BJCP_Study_Guide.pdf via pdftotext (sections Water Adjustment, Ions in Brewing, Chilling, Fining, packaging/priming) and matches the gate-verified deck T9-krausening-gypsum-fining.
T9. Define these brewing techniques and discuss their effects on the finished beer: a) kräusening, b) adding gypsum, and c) fining.
30% Kräusening · 30% Adding gypsum · 40% Fining [src: Study Guide, Brewing Process Questions – verbatim rubric]
Two things fall straight out of that, and both are worth more than any single fact underneath.
First: every part has two halves. "Define" and "discuss their effects on the finished beer" are separate demands, applied to each of the three. An answer that defines all three beautifully and never says what the beer tastes or looks like afterwards is answering half the question, evenly, across the whole page – which is the hardest kind of loss to notice while writing.
Second: fining is 40%, more than either of the others, and it is the part with the least conceptual content – it is a list of agents with a mechanism each. That is unusually good news: the biggest band here is pure recall, so it is the most reliably scoreable band in the technical pool. Spend your minutes proportionally: roughly 4 / 4 / 5 in a 15-minute answer, not equal thirds and certainly not "gypsum is interesting so I will write about water".
| Slot | Content |
|---|---|
| Define | The addition of freshly fermenting beer – an actively fermenting batch at the high-kräusen stage – to the beer being primed. The volume added is typically 20% by volume of the beer being primed. It is often practised with German lagers. [src: Study Guide, packaging/priming] |
| Effect on the finished beer | It serves two purposes: it carbonates the beer, and it helps clean up off-flavours generated from the previous fermentation. [src: Study Guide, packaging/priming] |
The natural contrast, and it costs one sentence: the other named repitching method is bottle conditioning – a fresh yeast starter plus corn sugar (glucose), a 250 ml starter for a five-gallon (20 L) batch, as is commonly done for Trappist-style Belgian ales. Same problem (fresh yeast at packaging), two traditions, two styles. Writing both shows you know why a brewer would pick one. [src: Study Guide, packaging/priming]
Do not claim the diacetyl reduction as a source fact. It is extremely tempting to write "kräusening reduces diacetyl" – fresh actively-multiplying yeast plausibly does exactly that. But the Study Guide's kräusening passage says off-flavours generally; it does not name diacetyl there. Write the sourced claim, then add the diacetyl point as your own reasoning if you want it: "it cleans up off-flavours from the previous fermentation – in a lager this is principally the diketone clean-up that a diacetyl rest also serves." That phrasing is honest and still shows the mechanism.
| Slot | Content |
|---|---|
| Define | Gypsum is calcium sulfate, CaSO4·2H2O (calcium sulfate hydrated with two water molecules) – one of the most common brewing salt additions, alongside Epsom salts (MgSO4·7H2O), non-iodized table salt (NaCl), calcium carbonate (CaCO3) and calcium chloride. Adding gypsum and Epsom salts is known as "Burtonizing", since it elevates hardness and sulfate concentrations to levels similar to those found at Burton-on-Trent. [src: Study Guide, Water Adjustment] |
| Effect on the finished beer | It delivers two ions, and you should name both. Calcium is the most important cation in brewing: essential for reducing mash pH into the 5.1–5.5 target range for starch and protein breakdown; it also keeps oxalate salts in solution (they cause haze and gushing if they precipitate), reduces tannin extraction, and aids protein coagulation in the hot and cold breaks. Sulfate accents hop bitterness and dryness at high concentrations, as at Burton. [src: Study Guide, Ions in Brewing] |
The detail almost nobody writes, and it is one sentence. The Study Guide states which volume you compute the addition against, and it is not the same volume for both purposes: for additions meant to improve the buffering capacity of the mash, use the volume of the water; for salt additions meant to change the flavour profile of the finished beer, use the target volume of the beer. [src: Study Guide, Water Adjustment] That is a procedural discrimination, it is sourced, it sits exactly on the "effects on the finished beer" half of the slot, and it is not on any of your current cards.
Style anchor for the effects half: Burton-on-Trent has calcium and sulfate far higher than any other city in the Study Guide's table, with the calcium nearly perfectly balanced by the bicarbonate – which is what let Burton brewers build the pale, bitter, dry-finishing British ales the sulfate axis is famous for. Gypsum is how you move any other water toward that. [src: Study Guide, Water and the development of beer styles]
The Study Guide categorises fining agents by when they are added, and reproducing that split is most of the band. Do not write one undifferentiated list.
Irish Moss and Whirlfloc tablets are kettle fining agents, added during the last 10–15 minutes of the boil, to aid coagulation and precipitation of proteins during the cold break.
[src: Study Guide, Fining + Chilling]
Added at the end of fermentation to promote sedimentation of residual protein-polyphenol complexes or yeast: silica hydrogels, gelatin, isinglass and polyclar.
| Agent | What it is, and how it works |
|---|---|
| Gelatin | Collagen-based, derived from animal hooves. |
| Isinglass | Collagen-based, derived from fish bladders. |
| Both are used by dissolving small quantities in hot (but not boiling) water and adding the solution to the fermenter a few days prior to racking or bottling. | |
| Polyclar | A powdered plastic whose positively charged molecules attach to the negatively charged protein-polyphenol molecules, forming larger aggregates that sink to the bottom of the fermenter. |
| Silica hydrogels | Named in the same list of post-fermentation agents. |
[src: Study Guide, Fining]
Fining removes proteins, protein-polyphenol complexes and yeast, so the beer clarifies. Two consequences worth spelling out, because they are what "effect on the finished beer" means here:
Six slots, ten minutes, cold: define and give the finished-beer effect for kräusening, gypsum and fining. Before you start, write "30 / 30 / 40" in the margin and split your minutes 4 / 4 / 5.
Count the slots when you finish, not while writing. Six ticks or it is not done. For fining, the split into two families counts as part of the definition – one list is a half-answer to the biggest band on the question.
1 Kräusening def: actively fermenting beer at high kräusen, ~20% by volume of the beer being primed, German lager practice. 2 Kräusening effect: carbonates + cleans up off-flavours from the previous fermentation (contrast: bottle conditioning, 250 ml starter + corn sugar per 20 L, Trappist ales). 3 Gypsum def: calcium sulfate CaSO4·2H2O; with Epsom salts = Burtonizing, raising hardness and sulfate toward Burton-on-Trent. 4 Gypsum effect: calcium drops mash pH into 5.1–5.5, keeps oxalates in solution (else haze and gushing), reduces tannin extraction, aids break formation; sulfate accents hop bitterness and dryness. Dose against water volume for mash buffering, against beer volume for flavour. 5 Fining def: kettle family (Irish Moss / Whirlfloc, last 10–15 min of the boil, aid the cold break; Whirlfloc = added purified carrageenan) and post-fermentation family (silica hydrogels, gelatin from hooves, isinglass from fish bladders, dissolved in hot not boiling water a few days before racking; polyclar, positively charged powdered plastic binding negative protein-polyphenol into sinking aggregates). 6 Fining effect: clarity by removing proteins, protein-polyphenol complexes and yeast; head retention is the trade; clarify cask Bitters and lagers, but not styles designated unfiltered.
If a slot came out thin, it is almost always slot 6 – the effects half of the biggest band. That is the cheapest place on this question to add two sentences.
A note on scope, because the study-group material and the exam question use the same words differently. The Study Guide's study-group Class 6 technical topic is "brewing procedures, including sparging, boiling, fining and carbonation methods" – broader than T9. The exam question T9 is the narrow one: kräusening, gypsum, fining. Sparging, boiling and the carbonation methods are covered as R0 procedure material in Lesson 16, where they earn their marks in the 30% procedure band. Do not import the water-chemistry essay into T9: gypsum is worth 30% here, and the eight-city table belongs to T8.