- What is the difference between IBU and bitterness perception?
- IBU (International Bitterness Units) measures the concentration of iso-alpha acids from hops in your beer. However, perceived bitterness is also shaped by your beer's residual sweetness (FG), pH, carbonation, and serving temperature. A high-SRM, malt-forward stout at 50 IBU can taste less bitter than a pale ale at 40 IBU, because the roasted malt character softens the perception. Use IBU as a formulation guide, not an absolute taste predictor.
- Why does the Tinseth formula give lower IBU than Rager or Garetz?
- The three main homebrewing IBU models (Tinseth, Rager, Garetz) were derived from different sets of brewing data and use different utilization curves. Tinseth values, published by Glenn Tinseth from Oregon State University research, tend to be conservative and are widely regarded as the most accurate for typical homebrewing conditions. Rager produces slightly higher numbers; Garetz generally produces the lowest. This calculator uses Tinseth. If a recipe from another source used Rager, their IBU numbers may look 10–20% higher for the same hop bill.
- What does SRM measure and how does it relate to beer color?
- SRM (Standard Reference Method) is a scale of beer color from pale to near-black. Values 1–4 are straw/yellow (light lagers), 5–10 are gold to amber (pale ales, IPAs), 10–18 are copper to brown (amber ales, brown ales), 18–30 are dark brown (porters, dark lagers), and 30+ are near-opaque black (stouts, robust porters). The Morey formula used here is more accurate at high MCU values than the older linear formulas. Note that your actual beer color may vary with your specific malts, water chemistry, and fermentation.
- What is brewhouse efficiency and how does it affect my OG?
- Brewhouse efficiency is the percentage of potential fermentable sugars you actually extract from your grain and transfer to the fermenter. All-grain homebrewers typically achieve 65–80%. Lower efficiency means your actual OG will be lower than theoretical maximum. If your measured OG consistently comes in below target, you can improve efficiency by milling finer, adjusting mash temperature (68°C / 154°F is typical), extending your mash time, or improving your lautering process. BIAB (Brew-in-a-Bag) setups often run 70–80% without a sparge.
- Can I save multiple recipes and load them later?
- Yes. Enter a name in the "Save & Load Recipes" section and click Save. Your recipe (grain bill, hops, batch size, and all settings) is stored in your browser's LocalStorage. It persists after you close the tab, but it is tied to this browser and device — it will not sync to other devices. To move a recipe, copy the browser session or note the values manually. Clearing browser data will delete saved recipes.