Cold brew coffee is smoother, less bitter, and naturally lower in acid than hot-brewed coffee from the same beans — but it is still not truly low acid coffee unless you start with beans roasted to a verified low acid standard. Here is the chemistry most cold brew guides skip entirely: the roasting process determines the base pH of your coffee. Cold brewing reduces some volatile acids that hot extraction releases, but it cannot undo the acidity created during roasting. Puroast cold brew achieves pH 5.82 — genuine low acid — because the roasting chemistry was done right before the cold brewing ever began.
Cold brew is brewed with cold or room-temperature water over an extended period — typically 12–24 hours — rather than with hot water over minutes. This fundamental difference in extraction chemistry produces three key results: less bitterness (heat accelerates extraction of bitter compounds), lower concentration of certain volatile acids (heat drives off chlorogenic acid degradation products), and a smoother, sweeter flavor profile overall.
The result is coffee that is naturally lower in certain acids than hot brew from the same beans — but the degree of reduction depends entirely on what acids were present in the first place. High-acid beans produce high-acid cold brew. Low-acid beans produce genuinely low-acid cold brew. The roasting chemistry sets the floor.
Equipment: A large mason jar or dedicated cold brew maker. Fine mesh strainer or cheesecloth. Kitchen scale (strongly recommended). Refrigerator space.
Coffee: Coarsely ground Puroast — Dark French Roast, Mocha Java, or Uganda Single Origin are all excellent for cold brew.
Water: Filtered water produces cleaner flavor. Chlorinated tap water can add off-notes to an 18-hour steep.
The standard cold brew ratio is 1:4 to 1:5 for concentrate (dilute before drinking) or 1:8 for ready-to-drink. Cold brew concentrate (1:4) gives you flexibility — dilute with water, milk, or oat milk at serving time. Most serious cold brew drinkers prefer concentrate because it keeps longer and allows you to customize each serving.
| Style | Ratio | Per Quart Water | Use |
|---|---|---|---|
| Strong concentrate | 1:4 | 225g coffee | Dilute 1:1 before serving |
| Standard concentrate | 1:5 | 180g coffee | Dilute 1:1 or use straight over ice |
| Ready-to-drink | 1:8 | 112g coffee | Serve directly over ice |
Cold brew requires a coarse grind — similar in texture to raw sugar or coarse sea salt. Fine grinds over-extract during the long steep and produce bitter, muddy concentrate that is difficult to filter. Most burr grinders have a dedicated coarse setting. If you are unsure, err on the side of too coarse — you can always adjust the next batch.
Add your measured coffee to your container. Add filtered, cold (or room temperature) water. Stir gently to ensure all grounds are saturated. Cover tightly. Steep for 12–16 hours at room temperature, or 18–24 hours in the refrigerator.
Room temperature steeping: faster, slightly more intense flavor, slightly higher acid extraction. Refrigerator steeping: slower, cleaner, slightly smoother. Both work well. Choose based on your schedule.
Place a fine mesh strainer over a large bowl or second jar. Pour the steeped concentrate through the strainer. For a cleaner, clearer concentrate, line the strainer with a paper coffee filter or cheesecloth before pouring. This double filtration removes fine grounds and produces a concentrate closer to commercial cold brew clarity.
Do not squeeze or press the grounds — this forces bitter sediment into your concentrate. Let gravity do the filtering. The process takes about 5–10 minutes.
Transfer filtered concentrate to a sealed glass jar. Refrigerate immediately. Cold brew concentrate keeps up to 2 weeks. Ready-to-drink cold brew keeps up to 1 week. Label with the date you made it.
| Method | Equipment | Best For | Brew Time |
|---|---|---|---|
| Mason Jar | $5–10 | Beginners, batch brewing | 12–24 hours |
| French Press | $20–60 | Integrated filter, easy | 12–18 hours |
| OXO Cold Brew Maker | $50–60 | Convenience, clean concentrate | 12–24 hours |
| Toddy System | $45 | Commercial-quality concentrate | 12–24 hours |
| Filtron | $35 | Large batch, very clean | 12–24 hours |
Puroast Dark French Roast cold brew concentrate (1:5 ratio), diluted 1:1 with filtered water. Serve over ice. No additions needed — the natural low acid profile makes this exceptional on its own.
Puroast Mocha Java cold brew concentrate over ice, diluted 1:1 with barista-style oat milk. The oat milk's natural sweetness complements Mocha Java's chocolate notes without any added sugar.
Puroast Uganda Single Origin cold brew concentrate (2oz) over ice, topped with sparkling water (4oz). Add a squeeze of orange peel. The carbonation and citrus accent the dried fruit notes in the Uganda bean.
Puroast House Blend cold brew concentrate (3oz) blended with 1 scoop vanilla protein powder, 1 cup almond milk, 1 cup ice. Shake or blend until smooth. 25g protein + coffee fuel in one drink.
Puroast Dark French Roast cold brew concentrate (2oz) with bourbon (1.5oz), vanilla simple syrup (0.5oz), over ice. Stir 20 times and strain. The low acid profile prevents the acid-bourbon interaction that makes standard cold brew cocktails harsh.
Yes — cold brew from the same beans is typically pH 5.0–5.5 vs pH 4.5–5.0 for hot brew. But neither is truly low acid. Puroast cold brew at pH 5.82 is the only verified low acid option — the roasting process achieves what cold brewing alone cannot.
12–16 hours at room temperature, or 18–24 hours in the refrigerator. Do not exceed 24 hours — over-steeping produces increasingly bitter, over-extracted concentrate.
Coarse — similar to raw sugar or coarse sea salt. Fine grinds over-extract during the long steep and produce muddy, difficult-to-filter concentrate.
Concentrate (1:4 ratio): up to 2 weeks. Ready-to-drink (1:8 ratio): up to 1 week. Always store sealed in a glass container in the refrigerator.
Medium to dark roasts produce the best cold brew. Puroast Dark French Roast, Mocha Java, and Uganda Single Origin all produce exceptional cold brew at pH 5.82 — smooth, rich, and genuinely low acid.
Puroast Dark French Roast — rich, bold, pH 5.82 — makes exceptional cold brew concentrate. Subscribe and save 15% on every bag.
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