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Iiittala + glass vocabulary

Iittala’s history

Iiittala’s designers

Iittala’s product use and care instructions (from Iittala’s guide)


The glass material used in Iittala’s products is high quality and lead-free, which is designed to meet the requirements for art and everyday glassware. It’s optically very clear and resists both chemical and mechanical wear. In terms of weight and refractive feature it meets the requirements of crystal so it can also be called as crystal. Iittala glass is manufactured in Iittala, Nuutajärvi and Humppila.


Timo Sarpaneva’s i-glass collection was introduced the first time in spring 1956. The new i-collection was modern glassware and each item in the collection had it’s own esthetical value. The collection’s sophisticated and simple beauty extended the triumph of Finnish art glass, which had continued several years. For the collection Sarpaneva designed a small red i-symbol, which has been the trademark of Iittala’s product collection from the 1960s and still it symbolizes the high quality of Iittala glass.


Iittala’s glass is designed to endure dishwasher wash. All Iittala’s glassware can be washed in a dishwasher. Place the glasses in the top rack of the dishwasher so that they do not touch each other during the wash cycle, because it can break the glass. Place other items on the lower rack of the dishwasher so that the water sprays won’t move the glasses on the top rack. It’s recommended to rinse milk glasses with cold water before washing in the dishwasher, because bleach can cause grayness in glassware. Short washing cycles and low temperatures (max +55°C) are recommended. Follow the detergent manufacturers’ instructions when measuring dishwasher detergent. Delicate stemware, pitchers and jugs, mugs, large-footed dessert bowls and glass of varying thickness (for example vases and art glass items) should be washed by hand. Varying thickness can cause glass item to break, because heating can cause tension in the glass.


Use glasses that are made of evenly thick glass to serve hot drinks. Warm up the glass by filling it up with warm water before pouring hot liquid. Place glass with hot liquid on a coaster, a napkin or on a wooden surface – never on a cold metal surface, because thermal shock can break the glass.


Warm up a glass bowl with warm water and let soup to cool down to +60°C, before pouring it in the bowl.


We don’t recommend microwaving i-glass, because dielectric heating can break the glass.


Always place candleholders on a fireproof base. Never leave a candle burning unattended. Don’t place candles in a drafty place or on top of a television. Never place a candleholder beneath or in the immediate proximity of combustible materials. Do not drop foreign objects (for example matches) into a candleholder or onto a candle. Never move a candle while hot, because the wick may shift in the melted wax near the edge of the candleholder and the heat can break the glass. Do not burn an ordinary candle right to the end, because the heat might break the candleholder. Use only good quality metalcupped tealight candles in a candleholder. In case the candle inside the candleholder flares, extinguish the candle by suffocating the flame. Leave an adequate gap between candleholders when designing candle arrangements. Never use gel candles in Iittala candleholders.


i-glass is not ovenproof.



The best way to ensure the i-symbol doesn’t come off is to wash glassware by hand. Before you place glassware into a dishwasher, press the symbol tightly into the glass, so that it sticks to the glass during the first wash and drying.


Soak glasses in a water-vinegar mix.


Hard water causes cloudiness in glassware. The harder the water is, the more likely cloudiness occurs. Use salt to soften the water or try different soap.


Some low-alkaline dishwasher detergents contain silicate, which causes metallic surface on a glass. This is actually an extremely thin silicate layer. In case metallic surface disturbs you, try silicate-free dishwasher detergent.


Burning lens phenomenon may damage objects and surfaces in the vicinity of the glass object. To avoid this, do not leave a vase filled with water or a lens-shaped thick glass object in direct sunlight.


Soak the vase in 1 dl laundry detergent to one liter of water. Scouring powder and scrubbing pads scratch and spoil the surface.

Glass vocabulary

cylinder finishing – manual finishing process to finish the edges of a glass item. Cylinder finishing is done next to a hot kiln and it’s typically used to finish art glass items and pitchers. A glass item that is blown to its shape is attached to metal rod with hot glass mass. Top part of the glass item is removed and it’s heated up again. When the item is hot the top part is cut open with scissors and that’s how the item gets its shape.

filigree glass – striped glass. In Finland most filigree glass is manufactured by Nuutajärvi Glassworks, which started manufacturing it in the end of 1850s. Kaj Franck revived the technique in the beginning of 1960s. Nuutajärvi glassworks used pre-casts in the manufacturing process. Colored glass filigree rods were placed in the pre-casts and when the glass was blown in the cast the rods stick to the glass starting and the item was blown until it’s finished.

polishing – previously polishing was a common way to decorate items. Glass is polished with rotating sanding sheets. Engraving and polishing resemble each other, but the size and result of sanding sheets differentiates these two. Nuutajärvi started manufacturing polished glass in Finland in 1850s.

furnace – the hot end of a glassworks, where the glass is formed.

furnace work – free forming.

i-Glass – glass made of Iittala’s own glass material, used to produce clear, durable and chemical resistant items, glass material is white and chemically very clean.

wetting off – cold water is poured on the separation line of the glass work and blowpipe. This causes a thermal shock. This perishes the separation point and when the blowpipe is tapped the glass item separates.

cooling – if a glass item cools down uncontrolled, tensions might be created between the outside and the inside of the glass and this can break the glass even after several years. That’s why glass items are cooled down in annealing oven. A finished item is heated to 500°C and then cooled down slowly so that tension is not created. Thin items cool down quickly, but thick items can take even weeks to cool down.

centrifugal casting – glass molten is poured into a mould, which then spins rapidly. The centrifugal force pushes the molten glass evenly against the mould walls and the decorations are created in the item. This technique is used to produce bowls and plates.

three-phase glass – glass molten is added with a spike to a mould-blown glass item. Stem of the glass is made with a machine or with stem scissors. New glass molten is added with a spike for the base and that is shaped with a press plate. In a two-phase technique stem and base are shaped at the same time.

crystal - the soda of the glass molten is replaced with potash (K2CO3) and approximately 30 % of the sand and lime is replaced with red lead. This heavy, clear and soft crystal molten is easy to polish, but when it’s soft if scratches and corrodes easily.

hot cutting – collar of the glass item is removed right after it’s finished. The collar part is melted with sharp gas flames. The glass item gets a thicker, ribbon-like edge.

block - a forming tool to shape molten glass. It looks like a scoop and it’s usually made of alder wood.

cold cutting – a more finished edge is done by cold cutting technique. An item goes through an annealing oven with a collar. After this the item is places in a spinning wheel and the separation point is scratched with a diamond blade. Then it’s heated with gas flames and the thermal shock separates the item. The uneven and sharp edge is polished to be smooth and shiny.

molten glass – inorganic melting product, which hardens when cools down, but it doesn’t crystallize. amorphous material

fundamental constituent: silica approximately 70 %

flux: soda approximately 17 %


stabilizers: limestone approximately 7 %

red lead

zinc oxide


cleansers saltpeter approximately 6 %



colors: chromium oxide, copper oxide, manganese oxide, titanium oxide, cobalt oxide, selenium, iron oxide, gold chloride

glass waste – cullet, glass chips or pint. Used in the melting process with quartz sand (for example high iron content of the quartz sand causes a green shade). Clean glass sand requires very high melting temperature 1700°-1800°C. Soda is added to reduce the melting temperature. Quartz and soda form water glass, which dissolves in water. Limestone is added to prevent the glass mass to dissolve in water and to improve the chemical and mechanical durability. In the melting process different cleansing and coloring agents are added. Cleansing agents bind gasses that are formed during the melting process and coloring agent color the molten glass and also prevent unwanted color shades.

mould – earlier moulds were made of wood, nowadays they are made of iron, steal or graphite.

mould pressed blown – when the blowing pipe and parison are hold still during the blowing process the molten glass is pressed against the mould. The engravings of the mould are transferred to the glass. Patterned glass and irregular cross-section glass items are produce with the mould pressed blown technique.

mould blown – the parison in the end of the blowing pipe is pushed into the mould and the molten glass is blown against the mould.

mould pressed –t he pressed glass process is started like a casting process. The bottom part of the three piece mould forms the shape and the pattern of the surface. Once the molten glass is poured a separate top piece is installed (so called model) and the molten glass is pressed between the moulds. The rim part is formed with a separate circle piece. Collar is not formed in this process.

mould spinning pressed – when the blowing pipe is rotated at the same time as blown, the parison rotates in the mould. A steam cushion is formed, which forms a smooth surface. Round and smooth items are produced with this technique.

mould casted – molten glass is taken from the kiln with a metal scoop and poured in a mould. This technique is used to produce candleholders and art items.

batch –the mixture of glass raw materials.

opal glass – molten glass is made cloudy with cryolite, which forms microscopic crystals with feldspar. These crystals reflect lights in a way that eyes see the glass as opal color. Opal color is formed when a glass blower adds a think layer of opal glass between clear glass layers. Opal glass is also called as milk glass or bone glass. Bone ash forms microscopic phosphorus pentoxide bubbles, which have the same light reflective impact as fat has in fat bubbles in milk; eyes see the reflective light as white.

parison – the tip of the blowing pipe is rotated in the hot molten glass inside the kiln. Accrued glass mass is spin against a steal blade and some air is blown inside the mass. This is how parison is formed.

iron rod mark – in the cylinder finishing process the iron rod leaves uneven surface on the bottom of the glass item. Heating the item smoothes the surface or it can be sanded down. Typically “ball sanding” technique is used and the method is called “balling”. That leaves a round mark on the bottom of the glass item.

blowing pipe - 1,2 – 1,5 meters long iron or steal pipe.

starting on top – more glass is added on top of the parison.

annealing oven – tunnel like oven. Glass items move slowly inside the oven on a metal belt from 500°C to room temperature.

stick air technique – a wet wooden stick is placed in the molten glass, the steam causes an air bubble inside the item.

free design – blown glass item is produced without mould using blowing pipe. Wooden scoops, tongs and spatulas are used in this technique.