Hard Cider Calculator: ABV and Blend Planner

The four classes. Cider apples are sorted on the Long Ashton system: acid above 4.5 g/L (0.45% malic) is sharp, tannin above 2.0 g/L (0.2%, Lowenthal method) is bitter. That gives sweet, sharp, bittersweet and bittersharp. The dashed lines on the map are those two cut-offs. Dots are colored by where each variety’s numbers fall, which isn’t always the class it’s sold under.

Blending is linear. Gravity points, acid and tannin mix in proportion to juice volume, so a 70/30 blend sits 30 percent of the way from the first juice toward the second. pH doesn’t mix that way, so measure the finished blend.

pH is an estimate unless you measure it. pH doesn’t average. Each juice’s pH comes from its published reading where there is one, or from an apple curve fitted to acidity where there isn’t. The planner then treats every juice as malic acid partly neutralized by potassium (pKa 3.40 and 5.20), works out how much acid and how much potassium each brings, mixes those by volume and solves for the blend’s pH [57, 58]. That’s the textbook way to relate acidity and pH [57], but it ignores the other acids and salt effects, so read it to about 0.1 to 0.2. Franklin read 2.8 at 7.8 g/L and Binet Rouge 4.5 in Montana at 3.3 g/L, which no curve predicts. Type your meter reading into the pH box and the planner uses it. Lea’s target is 3.2 to 3.8. Below 3.0 he adds no sulfite. Above 3.8, bring it down with malic acid first [15].

Sulfite by pH. Lea’s table: 3.0 to 3.3 takes 50 ppm, 3.3 to 3.5 takes 100, 3.5 to 3.8 takes 150. One Campden tablet in an Imperial gallon gives about 50 ppm (about 60 ppm in a US gallon) [15].

Gravity and alcohol. SG = 1 + Brix / (258.6 − (Brix / 258.2 × 227.1)). Alcohol shows as a range. The high end is (OG − FG) × 131.25, the usual homebrew formula. The low end is scaled to Lea’s rule of thumb that 1.070 makes about 8.5% [15], which allows for acids and other solids that read as gravity but don’t ferment. Very sharp juice reads higher than its sugar. Lea puts a 1 percent malic acid solution at about SG 1.004, and Jolicoeur figures Dolgo’s 25 g/L of acid adds about 10 gravity points [54]. That acid stays in the cider, so the planner raises the final gravity by 0.4 points for every g/L of acid above 5 g/L (the 5 g/L baseline is our assumption, the middle of Lea’s normal 3 to 7 g/L, since his 8.5 percent rule already covers ordinary juice). For the Dolgo ciders in [54] that predicts a finish near 1.008; they stopped at 1.009 to 1.012.

Tannin numbers. Long Ashton and WSU tannin is a permanganate (Lowenthal) titration in % tannic acid, and only that lines up with the 0.2% bitter line. Many newer trials report Folin total polyphenols in mg/L instead, which can’t be converted exactly. Where only Folin numbers exist, or none at all, the planner’s tannin is our estimate, and every tannin figure carries its own M, P or E flag. Even permanganate results depend on the lab: MSU WARC’s L-P tannin reads 2 to 3 times the Long Ashton and WSU figures for the same varieties (Binet Rouge 0.46% vs 0.21%, Hewe’s 0.52% vs 0.19%) [18]. So the planner blends on the Long Ashton scale, shows WARC tannin only as reported, and treats every tannin comparison as rough.

Acid units. Everything is shown as g/L malic acid. Citric (berries, pears) is converted ×1.047 and tartaric (grapes) ×0.893, so a fruit’s acid lines up with apple acid. WARC reports % malic, so 0.84% reads 8.4 g/L.

Style rules the planner follows. Ciders stay at least 75 percent apple and crab, and perries at least 75 percent pear. BJCP says fruit cider is typically at least 75 percent apple and that pear must be the majority of a perry, and UK duty rules cap pear in cider and apple in perry at 25 percent, a rule HMRC’s current guidance still carries [16, 53, 68]. Fruit other than apple and pear belongs in fruit cider; in other styles the planner only offers it as a labeled wildcard. High-acid and high-tannin fruit also has a usual top share. The Dolgo limit comes from Jolicoeur [14]; the others are our guidance.

Perry is different. Pears carry sorbitol, which yeast won’t ferment. Finnish pear juices ran 6.4 to 24.5 g/L [21] and Herefordshire perry can hold up to 25 g/L [52], so the planner leaves about 12 g/L in a pear’s final gravity and perry finishes near 1.004. Pears also carry citric acid, and malolactic bacteria turn it into acetic acid [65]. BJCP 2025 says perries should not undergo MLF “because acetification may result” [16], and one maker adds 25 ppm sulfite mostly to stop those bacteria [45]. Herefordshire perry is allowed a natural MLF [52], so it’s a risk to manage, not a law. True perry pears like Barland are sharp and tannic (SG 1.058, acid 0.92 and tannin 0.26, units not printed, from Brooks and Olmo) [44]; we don’t sell one yet.

Crabs and high-acid fruit. Dolgo runs about 25 g/L acid and Siberian crab about 27, so they’re seasoning, not base. Jolicoeur says no home orchard should be without some Dolgo [51], and that it’s difficult to use more than 15 percent in a blend [14]. Two makers’ Dolgo ciders stopped near 1.010 to 1.012, yet lab-tested 7.1 and 7.9 percent alcohol with 18 to 20 g/L malic left, so the acid is holding the gravity up, not unfermented sugar [54]. Black currant, sea buckthorn and the prairie cherries are the same story.

Sorbitol fruit. Aronia carries about 66 g/kg sorbitol [25] and Latvian rowan and aronia samples ran 32 to 72 g/kg [27]. Yeast won’t touch it, and MSU’s aronia wines never fermented fully dry [49]. The planner adds each fruit’s sorbitol to the final gravity. Commercial aronia juice blends often carry 2 percent or less [50]; the planner caps aronia at 5 percent.

Late fruit in short seasons. MSU WARC picked Binet Rouge, Wickson and several late bittersweets with starch-iodine readings of 1.7 to 4.8, short of ripe, even though the juice already ran 17 to 20 Brix [18]. The planner flags anything that ripens after about October 5 when your zone is 4 or colder. Pick late fruit before a hard freeze and let it sweat. Lea stores fruit two to four weeks so the last starch turns to sugar, and presses when an apple keeps a thumbprint [62].

Adjusting the juice. Table sugar adds about 46 gravity points per pound per gallon [59], about 2.6 g/L per point; Lea’s 12 to 15 g/L for 5 points agrees [15]. Malic acid raises acid gram for gram, and Lea adds it 1 g/L at a time. Calcium carbonate takes out about 0.75 g/L of acid (as malic) per g/L of carbonate, by the chemistry; winemakers quote 2.4 g per gallon for 0.1 percent acid as tartaric [61]. Bench test before taking out more than about 2 g/L (PIWine says 0.2 percent as tartaric), since it raises pH fast and can taste chalky or salty [61], and Lea would rather blend or, at a pinch, dilute [15].

Nitrogen. UVM found yeast-available nitrogen (YAN) under the 140 to 350 mg/L optimum in almost every cider juice it tested, as low as 28 mg/L in Franklin [4]. Pear juice is low in amino acids too. Low YAN means slow ferments and sulfur smells. 100 mg/L of DAP adds about 20 mg/L YAN [60]; Lea’s ceiling is 300 mg/L of ammonium salt plus 0.2 mg/L thiamine [15]. Skip it for keeved cider, which depends on low nitrogen.

Pectin. Crabapples, quinces, currants and plums are naturally high in pectin [64], and pears are too [65]. Pectic enzyme in the juice helps the cider clear [15], but it won’t make quince press: growers got next to nothing from a press and no help from the enzyme, so grate or cook quince first [66].

Keeving. The French and old English way to keep cider naturally sweet. Lea’s method: ripe, mostly bittersweet fruit from low-nitrogen orchards, at least SG 1.055; let the pulp stand up to 24 hours, then add pectin methyl esterase and, separately, calcium chloride (400 ppm at most); keep it near 5 °C until a brown cap rises, and rack the clear juice from between cap and sediment. That strips at least half the nitrogen, and the cider is bottled around SG 1.010 to 1.015 [63]. New enzymes work down to about pH 3.6 [63].

Ferment apart, blend after. Fruit that ripens a month apart is easiest to ferment as separate batches and blend once each cider is finished and tasted. Final blending by taste always beats the math.

Measure your own. Published numbers swing a lot by site and year. Golden Russet tests 6.6 g/L acid on the Washington coast, 8.4 in Stevensville, Montana and 9.7 in eastern Washington [2, 18, 55]. Hewe’s runs SG 1.060 on the coast and about 1.087 in Corvallis, Montana. Switch the planner to Montana numbers to see the difference. A hydrometer or refractometer, an acid titration kit and a pH meter cost less than one tree. Then click “use my own juice numbers” on any variety in your blend: your readings replace ours in this browser, show as Y, and drive the blend and the suggestions.