Working guidanceWe run this. It has produced results under the conditions stated on this page. · The full position record
Water, Minerals, and pH
Barley brewers can lean on generations of water-chemistry lore built around barley malt. Gluten-free brewing does not inherit that. When conversion depends on a designed external-enzyme program working on gelatinized sorghum starch, the mash environment — pH, calcium, and the ions that come along with your salt additions — stops being a detail and becomes part of the process.
None of this is doctrine. The only doctrine is no wheat, barley, rye, or oats. Everything on this page is a working baseline from commercial practice to validate on your own water, malt, and equipment.
Start with your source water
You cannot target a mash pH or a calcium level without knowing what you already have. Get a profile of your source water — at minimum calcium, alkalinity, chloride, and sulfate — and calculate additions from there. Treating tap water as a blank slate is how you end up chasing a mash that will not convert.
Mash pH
Mash pH is the single most important water lever, because enzyme activity is pH-dependent. The GFB working target is mash pH 5.5 to 5.6, measured and recorded at the actual process steps — not assumed from a salt recipe.
- Measure at the real conditions (temperature-corrected), not a cold sample hours later.
- Record pH by step. A batch record that shows the pH the mash actually experienced is what lets you connect a disappointing conversion back to a cause.
- Adjust with acid as needed to reach the target; note the addition.
A number without context is dangerous: 5.5–5.6 is where the GFB enzyme program was run, not a universal constant. Your enzyme products, grist, and water may move it.
Calcium
The GFB complete-process working baseline is approximately 100 ppm calcium — the working notes from the production program put the range at 100–150 ppm. Calculate the addition from your source-water profile and record calcium, chloride, sulfate, acid, and salt additions.
There is an honest open question behind that number, and it is worth stating plainly:
Novozymes brewing documentation states that Termamyl SC DS can operate at calcium levels below 20 ppm — that is an enzyme capability statement. Bard's commercial records, with period enzyme-distributor guidance for the Novozymes system, used a higher complete-process calcium condition (~100 ppm), but the exact original reason has not been recovered. Until it is: target ~100 ppm as the complete-process baseline, and do not read 100 ppm as a Termamyl minimum.
This is exactly the kind of number to validate, not worship — see The Reliable Mash, which carries the full protocol context.
Why we take this position
Position. Target approximately 100 ppm calcium as the complete-process working baseline for The Reliable Mash. Do not read it as an enzyme minimum. Calculate from your source water, record every addition, and validate the number on your own system.
Basis. Commercial production experience — Bard's ran this range — with the 100–150 ppm figure traced to 2019 enzyme-distributor guidance for the enzyme system in use. Working baseline, not a manufacturer requirement.
Why. The external-enzyme program only works inside the pH and mineral conditions it needs, and calcium is part of those conditions. The production record used about 100 ppm for the whole process and the process was reliable. Until the reason for the gap between that figure and the enzyme's own stated tolerance is recovered, the conservative number is the one we publish.
The problem forcing it. The original reason for the higher complete-process calcium condition was never written down and has not been recovered. That leaves a published number without a published rationale.
Compensation or ideal? A compensation. A conservative baseline is standing in for a known requirement. The ideal is a recovered rationale, or a measured floor across the whole process, so the number can be set to what the process needs and the chloride and sulfate that come with it can be chosen on purpose.
Evidence.
- Bard's production records at about 100 ppm complete-process calcium — commercial experience, the primary basis.
- 2019 enzyme-distributor guidance for the enzyme system, stating the level helps the enzymes work efficiently and advising restrained chloride and sulfate — supplier guidance, the located historical source of the range.
- The enzyme maker's documentation stating the liquefaction enzyme operates below 20 ppm calcium — an enzyme-capability statement, not a process target.
- Not held: the reason production used the higher figure.
Open contradictions. One, unresolved. The enzyme-capability statement (works below 20 ppm) and the production condition (about 100 ppm) point in different directions, and the record does not say why. Both are stated here; neither is averaged. This is the calcium question on the Problems page.
What would change our position. Recovery of the original rationale from the production or supplier record; or a controlled calcium ladder on the complete process — same malt, same enzymes, same system — judged on conversion, runoff, fermentation, and finished beer. Either would replace a conservative number with a known one.
Related research asks. Ask 10 — the calcium ladder: the experiment that would resolve this position's open contradiction.
Commercial interests. None. Gluten Free Brewer holds no financial interest in any enzyme or brewing-salt supplier.
Consequence if wrong. Process. Salts and the ions that ride with them, added for a reason that may not apply — or a conversion that suffers on a system that needed more.
Decision owner and status. Craig Belser · Current · baseline governed July 2026 · last reviewed August 2026.
History. July 2026: one earlier record combined the working baseline, its source, and the open question; it was split into three, and the source of the 100–150 ppm range was corrected from an earlier misattribution to a different supplier to the 2019 enzyme-distributor guidance. The number did not change.
Chloride and sulfate
Keep chloride and sulfate restrained where practical. This is Bard's process-specific guidance, not a universal water target — beer style still matters, and different designs want different balances.
The practical trap is that the salts you add for calcium bring these ions with them: gypsum adds sulfate, calcium chloride adds chloride. So a calcium addition is also a chloride/sulfate decision. Track every addition, because high levels can interfere with enzyme performance, and you want to be able to tell a flavor or process result from the mineral change that caused it.
Record it, then validate it
| Control | GFB working baseline | What to record |
|---|---|---|
| Mash pH | 5.5 – 5.6 | Measured pH by step, acid additions |
| Calcium | ~100 ppm (complete-process) | Source Ca, calculated + actual additions |
| Chloride / sulfate | Restrained where practical | Every salt addition and the resulting profile |
| Source water | Known before adjusting | Full starting profile |
Run these as a starting point, measure what the mash actually experienced, and let the finished beer and your conversion checks tell you whether to move them. Water is a process variable to control and prove — not a fixed recipe to copy.
Related: External Enzymes · Gelatinization · The Reliable Mash · Batch Records