Appam and hoppers

What appam is

Appam is the name of several South Asian rice foods. This page is about the fermented rice-and-coconut pancake cooked in a curved pan, called palappam or vellayappam in Kerala and hoppers in Sri Lankan English. Malayalam അപ്പം and Tamil அப்பம் are forms of the wider name, and Sinhala ආප්ප means hoppers. The pancake is a shallow bowl, with a thin, often crisp, lacy rim round a thicker, soft centre. It is cooked one at a time and eaten at once, at breakfast or in the evening.

The main ingredient is rice, soaked and wet-ground or used as rice flour. Coconut goes in as grated flesh, fresh coconut milk or prepared milk, and many recipes add a little cooked rice or a cooked rice-flour paste to soften the texture. Water, sugar and salt finish the batter. There is no universal ratio of rice to coconut.

The batter is fermented before cooking, in one of three documented ways: with no added starter, with naturally fermented palm toddy, or with measured baker's yeast. Spontaneous fermentation relies on microbes from the ingredients and equipment, toddy brings organisms from a separate palm-sap ferment, and modern yeast recipes add Saccharomyces cerevisiae on purpose. All can give fermented appam, but they are not microbiologically the same.

A curved pan, the appachatti, gives the shape. The cook pours batter into the hot pan and rotates it so a thin film climbs the sides and a deeper pool stays in the middle. With the lid on, the centre sets in moist heat while the thin edge dries and crisps against the pan, so the hopper has a crisp rim and a spongy centre without being turned. It is a cooked dish, not a kept starter. Idiyappam, string hoppers, are steamed strands of pressed rice flour, and unniyappam and other sweet fried appams are separate foods.

What the record shows

The word appam is older than the bowl-shaped pancake. Sanskrit apūpa names a family of cakes in early Indian literature, but an old reference to apūpa does not identify a fermented hopper, and ingredients, equipment and shapes cannot be reconstructed from a shared word. Appam still names fried, steamed and griddle foods.

The best-dated evidence is South Indian temple inscriptions. Andrea Gutiérrez finds an appam offering at Īśānamaṅkālam under the Chola king Parāntaka I, about 930 CE, that funds rice and ghee, with no fermented batter, coconut milk or curved pan. An inscription at Srirangam of about 1087 CE records a richer appam of rice, pulses, ghee, unrefined sugar, pepper, cumin, salt, bananas and coconut, and Tirupati records of 1393 and 1534 also name appam offerings. They were often sweet and tied to festivals, and Gutiérrez cautions that the sources do not show whether a cake was shallow-fried, moulded or cooked another way. None proves the modern toddy- or yeast-fermented hopper.

The present dish is firmly established in Kerala and Sri Lanka, with related traditions in Tamil Nadu. Kerala Tourism documents appam as a regular breakfast, including Malabar versions, and the Sri Lanka Tourism Promotion Bureau names hoppers as a local rice preparation. A 1989 Dutch Burgher Union of Ceylon publication describes hopper batter of rice flour, coconut milk and palm toddy cooked in a special iron pan, direct evidence of the recognisable modern dish and one traditional fermentation.

How the regional versions developed and influenced one another is unresolved, and claims that one community invented the hopper or that it crossed to Sri Lanka on a particular date need stronger proof. Microbiological studies from 2004 on confirm lactic acid bacteria and other microbes in fermented appam batter, while official recipes often use commercial yeast; that science cannot be projected back into medieval kitchens.

Yeast, bacteria and starch

Appam fermentation joins microbial gas production with changes in a hydrated rice batter. Where baker's yeast is added, Saccharomyces cerevisiae takes sugars through glycolysis to pyruvate, which becomes acetaldehyde and carbon dioxide and then ethanol while NAD+ is regenerated. The gas lightens the batter, so a yeast batter is chiefly an alcoholic fermentation, though acid-making organisms may be present.

Traditional or spontaneous batters also hold lactic acid bacteria. Jamuna and Jeevaratnam's 2004 work isolated a bacteriocin-producing lactobacillus identified as Lactobacillus acidophilus from appam batter, and a 2018 study isolated Pediococcus pentosaceus NKSM1 from fermented batter collected in Malappuram, Kerala. These are organisms in particular samples and not a universal starter. A 2014 experiment recorded rising Lactobacillus counts in batters fermented with sugar or dates and a fall in pH over five hours, with one date-syrup sample at pH 5.8, which is an observation and not a safety endpoint.

Lactic acid bacteria lower the pH by making lactic acid, and heterofermentative ones can add acetic acid, ethanol and carbon dioxide. The laboratory temperature used for one isolate does not give the right fermentation temperature for every household batter.

Rice starch gives the cooked structure, but yeast does not eat intact starch granules; grain enzymes and microbial amylases release smaller carbohydrates from accessible starch, and added sugar is an immediate fuel. Cooked rice or a cooked rice-flour paste brings in starch that has already gelatinised, changing viscosity and helping a soft centre. Coconut adds water, fat and flavour, depending on whether it goes in as flesh, first milk or diluted milk.

The shape comes from cooking as much as fermentation. The thin film at the pan's sides loses moisture fast and crisps, the deeper centre sets as starch gelatinises and rice proteins change, and the lid traps steam so the centre cooks without turning. Gas cells give a porous centre, but there is no wheat gluten network, so the batter behaves unlike bread dough, and swirling technique, particle size, consistency and pan heat matter as much as fermentation. Palm toddy brings yeasts, lactic bacteria and sometimes acetic acid bacteria, including Saccharomyces, but species found in toddy are not automatically those of the finished batter.

Making appam, and why

The rice comes first. In wet-ground Kerala methods raw rice is washed, soaked and drained, then ground with coconut and sometimes cooked rice. Kerala Tourism gives 500 g raw rice, one grated coconut, half a cup of cooked rice, half a teaspoon of yeast and three teaspoons of sugar, with the rice soaked about four hours and the batter fermented eight. Soaking softens the grains for grinding, fine grinding spreads the solids through the liquid, and the cooked rice adds gelatinised starch.

The recipe on this page is the rice-flour method from Kerala Tourism's Appam and Crab Masala: 1 kg of rice flour, 5 g of yeast, 500 ml of coconut milk and 100 g of kappi, a thick paste made by cooking rice flour with hot water. Yeast, flour, water and kappi are mixed thick and left about six hours, and sugar and salt to taste and the coconut milk go in after, with water to reach a pourable batter. The English text calls the ferment one night, six hours; the Malayalam version says six hours. The kappi pre-cooks part of the starch to set the batter's viscosity and a tender centre. Yeast should not go straight into boiling-hot kappi, though no cooling temperature is given.

Other batters differ. The NIFTEM grain-processing handbook describes appam of rice flour, coconut, sugar and toddy left overnight, with the toddy already fermenting and full of microbes. Kerala Tourism names toddy as the traditional leaven for kallappam, though its home recipe uses 2 g yeast with 500 g raw rice. A spontaneous batter uses neither yeast nor toddy and cannot be assumed to ripen at the same rate.

To cook, a small curved pan is heated and lightly greased, a ladle of batter goes in the centre and the pan is rotated at once so a thin coat reaches the sides with a thicker pool at the bottom. It is covered while it cooks, and the appam is ready when the centre is set and the edge lifts from the pan, and is served without flipping. The batter is made for one session, some recipes allow brief refrigeration of leftovers, and no safe period for indefinite refreshing is established, so cooked rice and fresh coconut need careful handling.

Kerala, Sri Lanka and relatives

In Kerala palappam usually means the thin-edged bowl served with stew or curry, and vellayappam is another name for white rice appam, though usage differs by household. Recipes vary in rice, coconut, cooked rice and whether fermentation is spontaneous, toddy or yeast. Kerala Tourism's Malabar recipe uses grated coconut and cooked rice, and another uses rice flour, coconut milk and kappi.

Kallappam is related but distinct. Its name comes from kallu, toddy, and Kerala Tourism calls naturally fermented toddy the traditional leaven, though its published version uses commercial yeast, coconut, cumin, onions, garlic and curry leaves. It is cooked more like a thick pancake on a flat pan and turned, and it should not be swapped for plain palappam. Vattayappam, a steamed sweet of fermented rice batter with cardamom, unniyappam, a small fried sweet, kuzhalappam, a crisp tube, and idiyappam are separate foods.

Sri Lankan āppa is cooked in a small curved pan with a pronounced bowl. Plain hoppers are joined by egg hoppers, an egg cracked into the centre before the lid goes on, milk hoppers with extra coconut milk, and sweet hoppers with jaggery or treacle. Sri Lanka Tourism lists plain, egg and honey hoppers, and Tamil records from Jaffna describe fermented rice-flour batter with coconut milk and commercial yeast.

Sri Lankan fermentation varies as well: the Dutch Burgher Union account uses palm toddy with rice flour and coconut milk, current recipes may use yeast, baking powder or bicarbonate, and chemical leavening alone is not the same fermentation. A 2026 account from Colombo describes a hopper maker using freshly ground rice flour and coconut milk with no added yeast. Medieval temple appams, with ghee, sugar, pulses, banana and coconut, are not shown to be today's fermented hoppers.

At the table

Appam is eaten hot with the edge still crisp. In Kerala it is a familiar breakfast and also appears at other meals; its mild rice-and-coconut taste soaks up liquid sauces, and Kerala Tourism pairs it with chicken stew, mutton stew, crab masala, vegetable stew, egg curry and fish or meat curries. The soft centre takes the gravy and the thin edge contrasts with it.

Each appam is cooked on its own, the pan heated, swirled, covered, emptied and used again, so a held pancake loses its crisp edge as the centre moisture spreads. The pan and the immediate serving are part of the dish.

Hoppers in Sri Lanka are breakfast, dinner and street food. Plain hoppers go with lunu miris, a spicy onion-and-chilli sambol, or with curry, or with jaggery and bananas; egg hoppers add a cooked egg; milk and sweet hoppers suit other occasions. Eaters break pieces from the rim to scoop up the filling or sauce.

String hoppers, indiappa or idiyappam, are steamed nests of pressed rice flour, not swirled fermented batter, though they are served with similar curries and coconut accompaniments. Vattayappam and sweet fried appams share the name and nothing else. The batter is not eaten raw, and the dish category does not depend on the fermentation system, since toddy, yeast and spontaneous batters can all become savoury or sweet hoppers.

Reading the batter and the pan

A fermenting batter expands, bubbles and smells mildly acid or yeasty. How much depends on the method, rice particle size, sugar, water and temperature. Yeast batter has a more controlled inoculum than spontaneous batter, and toddy batter depends on the condition of the separate palm sap. Bubbles show gas, not a particular community or safe acidity.

A dense centre with little air points to inactive yeast, too little time, the wrong temperature or too little fermentable sugar, and in spontaneous or toddy batters the organisms may differ from those expected. Do not leave a batter that will not rise at room temperature indefinitely; keep to the recipe's schedule.

Too thick a batter pools at the bottom and makes no thin rim, and too thin a batter runs unevenly, tears or leaves a weak centre. The batter should pour yet keep enough body for the central pool, grinding and the amount of kappi change it, and recipes leave the exact water to the cook because rice absorption and coconut-milk strength vary.

Pan faults are their own set. A pan that is too cool leaves the batter sticking and the edge pale and soft, one that is too hot burns the rim before the centre cooks, uneven rotation makes an irregular rim, and no lid leaves the centre unset. The bowl-shaped appam is covered and lifted out without flipping, unlike kallappam.

Rice needs food-safety care. Raw rice can carry Bacillus cereus spores that survive cooking, and several recipes use cooked rice that must have been cooled and stored properly. Food Standards Scotland advises cooling cooked rice promptly, ideally within an hour, keeping it refrigerated and using it within 24 hours, and Food Standards Scotland guidance also notes that reheating does not reliably remove preformed heat-stable toxin. A fermenting batter does not remove spores or toxins, and smell, bubbles or acidity cannot show that mishandled rice has become safe.

Fresh coconut and coconut milk need hygienic handling too, and fermentation is no licence to hold coconut batter at room temperature. Toddy has its own fermentation history and may carry alcohol and contaminants, and bubbles do not judge its quality. The egg in an egg hopper must be cooked and handled properly. No single pH, storage period or count applies to every batter, and a measured laboratory pH is not a safety endpoint for a household batter. Discard batter with mould, odd colour or a putrid smell instead of adding more yeast, sugar or rice. Judge the hopper by whether the rim has cooked and the centre has set, not by bubbles in the raw batter.