Liverwurst 101

Source: https://www.tripsavvy.com/all-about-the-wurst-leberwurst-4036269

GERMANY !!! 

When you think of Germany, what comes to your mind?
Football? ⚽🏆
A certain man with a certain moustache?
Beer and Oktoberfest? 🍺🍻
Fast cars on the Autobahn? 🚗💨
Long words that are a mouthful to pronounce? (Unabhaengigkeitserklaerungen…)
Extreme punctuality? ⏰

What about leberwurst? Have you ever heard of leberwurst?
Leber (not Bieber) means “liver”, while “wurst” is actually the German word for "sausage" (it rhymes with "worst" but does not mean anything bad!).

Fun fact: Germany produces over 1200 types of sausages and distinguishes them as either raw, cooked (Bruhwürst), or precooked (Kochwurst).

So, liverwurst is basically precooked liver sausage, which is a German delicacy, but can also be found in other European countries like Austria, Finland, and the Netherlands. However, it does not always have to be in a sausage form, as it can also be made into a paste (aka “pate”), which is spreadable and usually eaten with sandwiches. Traditionally, liverwurst was only prepared on special occasions, but nowadays it has become a regular part of the German staple. From a manufacturer’s perspective, it maximises the utilisation of unpopular raw meats and meat byproducts such as tripe, heart, backfat, and lungs, thus adding value to these raw materials.

While liverwurst is a pretty generic name, distinct and unique variations of liverwurst exist in various regions across Germany, which may include additional ingredients like onions, bacon, mushrooms and cowberries (the latter two are the exception rather than the rule). Variations may also occur through different processing methods such as smoking (e.g. Thüringer Leberwurst).

 

Source: https://www.germandeli.com/Siegis-Hausmacher-Leberwurst-Liver-Sausage-Frozen

 

 

Source: https://www.germandeli.com/Kochers-Kassler-Leberwurst-Kassler-Liverwurst-coarse-approx-8oz

 

INGREDIENTS 

It comes as no surprise that one of the main ingredients of liverwurst is, well, liver – usually pork or calf liver, although beef and mutton liver are viable alternatives. It must contain at least 10% liver, while premium versions may contain more than 25% liver. In fact, all products sold in the US bearing “liver” in the product name must have at least 30% liver. Other major ingredients include fat and meat (usually pork or veal), while minor ingredients include salt, and spices such as black pepper, marjoram, thyme, bay leaf, and allspice.  Salt (2.5-3%) contributes to the flavour, retards microbial growth, and extracts myofibrillar proteins which help to bind and stabilise the emulsion. Extenders such as dried skim milk reduces formulation costs, increases yields, and improves emulsion stability.

Summary of typical ingredients used in making liverwurst

Ingredient	Remarks	Proportion (%)	Function(s) / Impact(s)
Liver	Pork/Beef	25-55	Colour, flavour, texture
Fat	Pork	20-40	Colour, Texture
Meat	Pork/Beef	30-40	Colour, flavour, texture, yield, nutritional value
Salt		2.5-3	Flavour, texture
Spices		1-2	Flavour

PROCESSING

The liver and meat are cooked by parboiling (T < 80 ^oC, 30-90 minutes) before grinding them together with the other ingredients. The liver may be scalded to reduce the surface microbial load and remove bitter flavours. Alternatively, the raw liver may be homogenised separately until bubble formation is observed before mixing with the cooked meat and fat later in a silent cutter. 

The mixing can be done either under hot or cold condition. For hot-processing, the meat and fat mixture needs to be maintained within 58-60 ^oC to ensure the fat has melted while the proteins in the meat has denatured. The homogenised liver should be added when the mixture has cooled to below 60 ^oC to prevent the denaturation of liver proteins. The pieces of meat may be cut prior to boiling or grinding to facilitate the grinding process. The resulting paste is finer and more spreadable compared to that of cold-processing. For cold-processing, the parboiled meat and scalded fat are chilled to below 25 ^oC before mixing to produce a firmer product with richer liver taste and aroma. Depending on the extent of grinding or chopping, the resulting paste can be coarse or fine. Chopping under vacuum can help to produce liverwurst that is darker, smoother, and denser as less air is entrapped. The paste is then stuffed into casings. 

At this point, the liverwurst may be cooked by boiling and/or cold-smoking, depending on the desired finishing and flavour profile. In the US, Braunschweiger is a type of liver sausage that is always smoked. After cooking or storage, the liverwurst should be kept chilled at 0-4 ^oC.

General processing flow in making liverwurst

COMPOSITION, STRUCTURE & BIOCHEMICAL CHANGES

From a structural point of view, the liverwurst is an oil-in-water emulsion. Liver per se is high in protein but has little fat. Thus, the proportion of fat used (usually from pork belly) has an impact on the texture and appearance of the liverwurst; it appears dry when fat is less than 20%, while it looks fatty and the fat taste is more pronounced when fat exceeds 40%. Fat content of 30-42% provides a nice meat-liver aroma. Since the proteins from the meat have been denatured during parboiling, the emulsion is mainly stabilised during mixing by the proteins from the liver, which may be aided by adding extenders such as skimmed milk powder. 

Nutritionally speaking, it is about 25-38% fat, 12-14% protein, and 6% carbohydrates. It also contains the goodness of liver, specifically iron as well as vitamins A and B12. However, its sodium and fat content can be rather high as well. In fact, it has significant amounts of unsaturated fats and pro-oxidant metals such as copper and iron from haemoglobin, which makes lipid oxidation one of the main concerns during storage. Lipid oxidation may lead to undesirable green, brown, or black discolouration, as well as off-flavours. The shelf life of the liverwurst can be improved by a careful selection of the casing, processing method (e.g. smoking), as well as choice of additives such as antioxidants. In commercial products, sodium nitrite, sugar as well as extenders such as milk powder may also be added. Residual nitrite (50-120 ppm) can help to stabilise the pink colour of Braunschweiger liver sausages.

As for the colour of liverwurst, it can range from gray to pinkish hues depending on various factors such as the ratio of liver to fat and meat used. Curing agents such as nitrites may also contribute to more pinkish colours. Meanwhile, the liver also has its characteristic flavour notes. The bile ducts are usually removed and the liver may also be soaked before further processing to reduce bitterness.

 

Rough composition of liverwurst

To sum it all up, liverwurst is an emulsion of fat in an aqueous medium that contains liver proteins to stabilize the emulsion. However, all the ingredients, be they major or minor, contribute to the overall flavour, colour, and texture of the final product.

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