Dataset

The WSU Mount Vernon cider cultivar trial

Fifteen seasons of European cider fruit grown in the Skagit Valley, and the clearest evidence CiderHQ holds that a cider apple’s class is a statement about a place as much as about a fruit.

Do English cider apples behave the same way when they are grown somewhere else?

No, and this trial is where that is documented rather than asserted. Washington State University planted European cider cultivars at Mount Vernon in a maritime climate chosen as the closest North American analogue to the English West Country, measured them over fifteen seasons, and published both its classification thresholds and its figures.

Seventeen of the seventy-three cultivars classify differently in the Skagit Valley from the way they classify in England. The programme says so itself, in as many words: some cultivars are classified differently at this site than they were classified in England.

The programme

Transcribed from the source as published. Nothing in this panel is CiderHQ’s wording.

Site: Northwestern Washington Research and Extension Center, Mount Vernon, Skagit Valley, Washington
Period: 2002–2017
Cultivars transcribed: 46
Measurements: 311
Values withheld: 4 — see limitations
Classifies under: long-ashton

Climate. Maritime, with cool summers and mild wet winters — the closest North American analogue to the English West Country, and the reason the programme planted European cider fruit here rather than east of the Cascades.

Method. Juice characteristics measured on 250 mL of pressed juice; juice yield from 25 fruit, 2015–2017 only. Bloom density, productivity and blind wood are the site’s own subjective 1–5 ratings. Figures are means across the seasons each cultivar was in the trial.

What the source says about itself

The site classifies under the English acid-and-tannin scheme and states its cut-offs — tannin 0.2%, acid 0.45%. It also states plainly that “some cultivars are classified differently at this site than they were classified in England.”

One cultivar, four measurement programmes, four sets of numbers — and the fourth is not a juice analysis at all. This is why CiderHQ never averages across studies.

Described in full

Shape: Four stacked panels, one per programme, each naming the place, the period and the substrate that was analysed. Within each panel the figures that programme published for Kingston Black are listed with their units. The fourth panel is set apart by a dashed border and a heading that reads "finished cider, not juice".
WSU Mount Vernon, Skagit Valley, Washington, 2002–2017, juice: pH 3.51, total acid 0.61% w/v, total tannin 0.15% w/v, specific gravity 1.055, 13.3 °Bx. A maritime North American site chosen as the closest analogue to the English West Country, averaged across the seasons the cultivar was in trial.
USDA-PGRU Geneva, New York, 2017, juice: pH 4.23, titratable acidity 2.1 g/L, total phenolics 1,080 mg/L, 12.5 °Bx. One season, one harvest, in a continental climate with hotter summers and colder winters than the Skagit Valley. The pH is 0.72 units above the Mount Vernon figure for the same cultivar.
Long Ashton, Somerset, 1905–1975, juice: Total acid 0.58% w/v, total tannin 0.20% w/v. A seventy-year composite from the station whose figures underlie the English classification. Its tannin figure is a third higher than Mount Vernon’s for the same fruit.
Geneva, New York, late 1970s, finished cider: Finished pH 3.56, finished total acid 0.58% w/v, finished total tannin 0.062% w/v. Set apart because it is a different quantity with the same name: fermentation, fining and time remove phenolic material, so this tannin figure is roughly a third of the Long Ashton juice figure and cannot be read as disagreeing with it.
What the figure argues: The pH spread across the three juice analyses is 3.51 to 4.23, which is large enough to change what a maker would do about it, and none of the three is an error. A measurement is a statement about a fruit and a place and a season and a method. Averaging the four would produce a number that no orchard ever grew and no laboratory ever measured.

What it adds

It publishes thresholds as well as figures, so every entry can carry both the class the site lists and the class the site’s own numbers imply. The gap between those two is the finding.
It measures juice yield, which almost nothing else does, on twenty-five fruit per cultivar across three seasons.
It disowns one of its own accessions in print — “not the true Tremlett’s Bitter” — and CiderHQ withholds every figure from that cultivar rather than publishing a measurement of the wrong tree.

What it cannot be asked

Stated as limits rather than as apology. A dataset with known bounds is more useful than one presented as complete.

Four published figures cannot describe real fruit: an apple recorded as 258 inches across, two juice yields that would need a press to recover more liquid than the fruit weighed, and Bramley’s Seedling at 0.11% acid against pH 3.12. Each is withheld with its reason attached rather than republished or quietly corrected.
Figures are means across the seasons each cultivar was in the trial, and the number of seasons is not the same for every cultivar.
Bloom density, productivity and blind wood are the site’s own subjective one-to-five ratings, kept as its scale rather than reinterpreted.

Why these figures are not universal

The whole point of the trial is that these numbers are local. A maritime North American valley at a different latitude, with different day length, different summer heat accumulation and a different soil, produced fruit that a scheme built in Somerset sorts into different boxes. Reading a Mount Vernon tannin figure as the tannin of the cultivar would be to draw exactly the conclusion the programme’s own caveat forbids.

What was measured

Every property in the transcription, with how many cultivars carry it. A property measured on some cultivars and not others is a gap in the source, not in the transcription.

Properties recorded across 46 cultivars in The WSU Mount Vernon cider cultivar trial
Property	Cultivars	Reported in
Total tannin	45	Percent weight per volume
pH	45	pH
Specific gravity	45	Specific gravity
Brix	45	Degrees Brix
Total acid	44	Percent weight per volume
Fruit diameter	44	Millimetres
Juice yield	43	Litres per tonne

Total tannin across every cultivar in this dataset that carries it — 45 of them, from 0.820 down to 0.070 % w/v. Every figure here comes from this one programme, measured by one method in one place, which is the only arrangement under which a comparison like this is sound. Nothing on this chart may be read against another dataset’s column.
Cultivar	Total tannin (% w/v)	Where it sits in this study’s range
Médaille d’Or	0.820
Reine des Pommes	0.520
Bramtot	0.500
Chisel Jersey	0.420
Marie Ménard	0.420
Vilberie	0.410
Lambrook Pippin	0.360
Nehou	0.340
Kermerrien	0.320
Fréquin Rouge	0.300
Porter’s Perfection	0.300
Doux Normandie	0.290
Stoke Red	0.280
Stembridge Jersey	0.270
Domaines	0.260
Dabinett	0.240
Harry Masters’ Jersey	0.210
Major	0.210
Muscadet de Dieppe	0.210
Yarlington Mill	0.210
Blanc Mollet	0.200
Breakwell’s Seedling	0.200
Bulmer’s Norman	0.200
Cap of Liberty	0.200
Fillbarrel	0.190
Hewe’s Crab	0.190
Campfield	0.170
Foxwhelp	0.170
Brown Snout	0.160
Brown Thorn	0.160
Kingston Black	0.150
Bedan	0.140
Michelin	0.140
Taylor’s	0.140
Sweet Coppin	0.110
Tom Putt	0.110
Golden Russet	0.100
Harrison	0.100
Bramley’s Seedling	0.090
Redstreak	0.090
Graniwinkle	0.080
Roxbury Russet	0.080
Gravensteiner	0.070
Grimes Golden	0.070
Sweet Alford	0.070

Ordering only. Where a figure was published as a range the midpoint is used to place the row, and the range itself — not the midpoint — is what appears on the cultivar’s own page.

What it can be read beside

The commonest way to misuse this corpus is not to misread one figure but to put two side by side that were never measuring the same thing. This is the judgement, stated.

Whether The WSU Mount Vernon cider cultivar trial may be read in one column with the site’s other datasets
Dataset	Verdict	Why
The Long Ashton cider apple table	Partly comparable	Same units and same classification scheme, which is what makes the disagreement legible. The columns line up; the orchards do not.
The USDA-PGRU germplasm characterisation	Not comparable	Both are North American and neither shares a convention with the other. Mount Vernon reports acid as percent weight per volume malic and tannin by permanganate; Geneva reports titratable acidity in grams per litre and phenolics by the Löwenthal titration.

Where a dataset is not listed, no judgement has been recorded and the safe reading is that the two have not been checked against each other. CiderHQ never averages across studies: how evidence is handled sets out why.

Cultivars in this dataset

Each carries this programme’s figures on its own page, alongside whatever else has measured it.

Sources

What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.

Washington State University cider research programme
Washington State University Northwestern Washington Research and Extension Center · university · passage verified 2026-08-24
The single most useful open cider dataset CiderHQ has found. The programme’s cultivar performance database gives juice chemistry, orchard behaviour, bloom and harvest timing and cider-maker tasting notes for 73 cultivars grown at one maritime site over fifteen years, and — unusually — publishes its classification thresholds alongside its figures, so the classification can be checked rather than taken on trust. It also states outright that its results diverge from the English ones. Read in full on 2026-08-24 and transcribed into `data/trials/wsu-mount-vernon.ts`; four published figures were found to be impossible and are withheld there with their reasons.