Diagnosis of Faults

The Diagnosis of faults in wine

To use the table, look for the fault in the left-hand column. In the right-hand column is found either the cause or reference numbers for later diagnosis.

Visual Faults
1	Haze or sediment		See 36
2	Patches on surface	}	Mycoderma infection.
3	Skin on surface	}	Mycoderma infection.
4	Oil on surface		Pre-acetification.
5	Wine thicker than usual		Lactobacillus infection.
6	“Ropes” in wine		Leuconostoc infection.
7	Wine looks like slime		Toropsulosis infection.
8	Layering in wine		Wine recently blended. Allow longer aging.
9	Wrong color for style		See 42
Test Entries (Taste/Smell)
10	Smell of bad eggs		Hydrogen sulphide in wine.
11	Vinegar	}	Acetified wine.
12	“Tart”
13	Acetic acid
14	Peardrops
15	Mousel	}	Butyric acid bacteria infection.
16	Rancid
17	Fishy
18	Burnt	}	Wine either over-cooked or intended as Madeira type. Charcoal fine if former.
19	Caramel	}
20	Corked	}	Cork infection. Discard wine.
21	“Swimming bath”	}	Cork infection. Discard wine.
22	Asbestos	}	Filter medium not washed before use. Discard wine.
23	Cardboard
24	Paper
25	Earthy		Wine over-fined with Bentonite or dirt from ingredients.
26	Yeasty	}	Young wine. Allow to mature.
27	Aldehydic	}	Young wine. Allow to mature.
28	Astringent		Too much tannin.
29	Over or under acid	{	Reduce with calcium carbonate Or Add acid and mature
30	Bitter		Lactobacillus infection with mannitol.
31	Cooked		Ingredients boiled too long.
32	Prickly		CO₂ still present. Fermenting or malolactic fermentation.
33	Musty		Wine on lees too long. Try charcoal.
34	Medicinal		Too little acid. Addition has poor chance of improving wine.

Taste/Smell
35	Mousey after taste	Lactobacillus infection
36	Haze with bubbles	See 37
36	Haze without bubbles	See 39
37	SG falling	Active ferment. Continue
38	Acidity falling	Malo-lactic ferment
38	Acidity static	Secondary ferment
39	SG 1020 or more	Stuck ferment (see entries)
39	SG 1020 or less	See 40
40	Haze with sediment	See 41
40	Haze without sediment	See test entries to find cause
41	Wine recently racked	See test entries
41	Wine not recently racked	Rack and reassess after 3 months
42	Wine meant to be red	See 43
	Wine meant to be white	See 44
	Wine meant to be Rosé	See 45
43	Wine too dark	Too long on pulp, or too much fruit
43	Wine too pale	Not enough pulp ferment, or too little fruit
44	Wine too dark	See tests
44	Wine too light	Not enough fruit
45	Wine too dark	Too long on pulp
	Wine too light	Not enough pulp ferment
	Orange tint in wine	Poor blend of red and white
46	Brown color in wine	If sherry or dessert wine – correct
46	Brown color in wine	If white wine – oxidation has occurred

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