The science of great sausages

What makes a good sausage?

So, you’re making sausage. You grind up meat and fat and stuff it in a casing and cook it. Why doesn’t it all just fall out of the casing in a crumbly mess once you’ve cooked it?

It might do… if you haven’t followed some of the core principles of sausage making

What makes a good sausage?

Safe to eat, a good texture, flavoursome, and its got to look appealing

There’s a a huge amount of science involved in sausage making and curing, and a wealth of sources available online if you choose to delve a little further. However i’ve attempted to simplify and summarise the main scientific reasons for employing the techniques that are used on this site, and on others.

Safe to eat

When making sausages, you grind up meat and fat. Doing so drastically increases the surface area available for bacteria and spoilage. This is why butchers don’t get mince meat delivered, its processed on site!

You want to limit the possibility of bacterial growth as much as you can, we do this by making sure everything is as clean as possible and as cold as possible, not just at the start but throughout the production process. We’ll also ensure safety by cooking things correctly!

Its important to know about the 'Danger Zone':

“Bacteria will grow at temperatures above 8°C and below 63°C – this is known as the ‘Danger Zone’ for microbial growth. That’s why we advise that the safest way to defrost food is in the fridge overnight. By defrosting in the fridge, your food should never enter the ‘Danger Zone’. Your fridge should be at 5°C or below as some bacteria can grow at lower temperatures than 8°C.”

Reference: https://www.food.gov.uk/safety-hygiene/chilling

So a few tips to ensure safe sausage making and reduce the risk of bacterial contamination and illness:

• Always wash your hands for at least 30 seconds with soap and water before beginning to work and after changing tasks or after doing anything that could contaminate your hands such as sneezing or using the bathroom.
• Start by cleaning equipment and clean thoroughly after using. Be sure all surfaces that come into contact with meat are clean.
• If using frozen meat, thaw it in the fridge on the lowest shelf to avoid dripping of juices on other foods. Keep raw meat separate from other foods.
• Marinate raw meat in the refrigerator.
• Keep meat as cold as possible (4c or lower) during processing.
• Refrigerate your grinding and stuffing equipment before processing.

A good texture

Back to the principle question: Why doesn’t it all just fall out of the casing in a crumbly mess once you’ve cooked it?

The mixture that is prepared and stuffed into sausage casings is often referred to as a "meat emulsion”. This is a dispersion of fat particles in water held by the action of salt-soluble, heat-coagulable proteins  - such as myosin (one of the proteins responsible for muscle contraction). Being salt soluble means that it is soluble in a weak salt solution and heat coagulable means that upon heating they form a solid or semi solid.

Myosin creates a cohesive “gel” that binds a sausage mix together, ensuring a juicy, flavourful mix. So we need to extract Myosin from the meat, into solution with water and salt and disperse it through the mix so that it can encase fat. When heated this will coagulate the protein and will suspend the fat particles in a matrix like structure. No crumbly mess.

You can over or under do the bind. With too little myosin available, fat and liquid will be lost and you’ll get a crumbly mess. Too much and a rubbery texture will be produced.

How do we activate the myosin?

With very clean hands, mix the sausage with the salt and spices thoroughly, after the first grind (i prefer to do this by hand rather than mixer), continuing to knead until the mixture starts to get really sticky. At this point the salt-soluble proteins have been extracted. On your first couple of attempts it’s difficult to judge at which point this is. You’ll be surprised how sticky the mixture gets! After a few minutes of mixing (If your hands go numb and hurt whilst doing this, you’ve got them temperature right!) make a little burger like patty and stick it upside down to your hand, if it sticks firmly and doesn’t fall, your pretty much there!

I leave the meat mixture with the salt, herbs and spices, in the fridge for 30 minutes, lightly mixed, to allow the salt to go to work before the second grind and thorough mixing.

Getting the right balance

To extract the meat binding proteins, we need to create a salt solution. Getting the right amount of salt is important here. Generally sausages contain about 1.8 - 2.2% salt by weight and can be adjusted to taste. Make sure you use a fine salt so that it dissolves easily.

Fat is important for taste and texture. Generally a ratio of 70 / 30 lean meat to fat ratio is desired.

Different cuts of meat and different animals possess different amounts of protein, a subject for another guide..

Cold, cold cold

I can’t stress enough how important it is to keep the meat and fat cold, prior to and during processing, to stop the fat smearing, separating and producing a mealy, crumbly textured sausage. As mentioned previously and on other guides on this site:

• Cool the meat and fat and equipment as instructed prior to and between stages
• Ensure that blades are sharp in the grinder to ensure minimal smearing and minimal heat generated by friction

Flavoursome

What’s the point of making a sausage with perfect consistency that doesn’t have any flavour?

Getting the right amount of salt is important here. Generally sausages contain about 1.8 - 2.2% salt by weight and can be adjusted to taste.

After you have made your sausage mixture, it’s helpful to fry up a patty to test before committing to the stuffing. This is the easiest point at which you can correct things!

Pan frying particular spices really helps bring out the flavour and whilst it might be obvious it’s important to note that fresh herbs, or newly bought and well kept dried herbs and spices bring the most flavour to the table.

Buying meat from a reputable butcher also helps and doing so often provides access to other important ingredients like sausage casings and back fat, that might be harder to find elsewhere on the high street.

An appealing look

“The first taste is with the eye” say some. Sounds painful to me. However there’s something in it. Your perfectly formed creation won’t be as appetising if it’s split open, or an anaemic shade of grey.

If you have a sous vide, it’s a fantastic way to cook sausages to perfection, but if you don’t finish them in a hot pan to develop an enticing colour and some caramelisation - they wont look too appetising!

It’s hard to beat this article for an extensive guide: https://www.seriouseats.com/2016/02/the-food-lab-guide-sous-vide-sausage.html

Over stuffing can spoil your creation at the last minute, have a read of how-to-make-sausages that will detail how to avoid over stuffing.

Cooking at too high a heat can also lead to bursting or separation of fat, have a read of how-to-cook-sausages, a guide that will walk you through the best practices!