Mashing
Mashing is the step where milled grain meets hot water and starch becomes sugar. It is the engine of the brewing process — the chemistry that determines how much alcohol the yeast can make and how much body the finished IPA carries.
#What Happens in the Mash
When the grist is mixed with water at 63–70 °C, the malt's natural enzymes activate and break long starch chains into fermentable and unfermentable sugars. This is conversion, and it is usually complete within 30–60 minutes.
Two enzymes do the heavy lifting:
| Enzyme | Optimal temp | Produces | Effect |
|---|---|---|---|
| Beta-amylase | 60–65 °C | Maltose (fermentable) | Dry, attenuated beer |
| Alpha-amylase | 67–72 °C | Dextrins (unfermentable) | Fuller body, more residual sweetness |
#Mash Temperature Is a Style Lever
Because the two enzymes favor different temperatures, the mash temperature directly shapes the beer.
- West Coast IPA — 64–66 °C for a crisp, dry, highly attenuated beer that lets bitterness shine.
- New England IPA — 67–68 °C to leave dextrins for a soft, full mouthfeel.
- Double IPA — 64–65 °C, often plus simple sugar, to keep a big beer dangerously drinkable.
Mash temperature is one of the highest-leverage choices a brewer makes. Two degrees can be the difference between "thin" and "balanced." See The Science of Mouthfeel.
#Mash Thickness and pH
- Thickness — typically 2.5–3.5 L of water per kg of grain. Thinner mashes favor fermentability.
- pH — target 5.2–5.5 at mash temperature. Correct pH improves enzyme activity, extraction, and protects against astringency. This is where Water Treatment for Brewing pays off; the Water Chemistry and the Sulfate-Chloride Ratio is set here.
#Single-Infusion vs. Step Mashing
Most IPAs use a single-infusion mash — one temperature held for the full rest — because modern malt is fully modified. Step mashes (a protein rest, then conversion) are occasionally used for high-adjunct New England IPA grists, though usually unnecessary.
An iodine test confirms starch conversion is complete: a drop of mash that stays amber (not blue-black) means you are done.
Once conversion is complete, the sweet wort is ready to be separated from the grain in Lautering and Sparging.