Getting the correct consistency or base for your ice cream mix is key to its success, and it can be achieved in a number of ways, depending on timescales and skillset.
Ice cream is essentially an emulsion (made up of sugars, milk solids and fat dispersed into milk or water), as well as being a foam created as a result of air bubbles being incorporated in the batch freezer. But how does it keep its structure? The answer is by the addition of stabilisers and emulsifiers.
Emulsifiers provide stability and give ice cream its smooth body and texture, as well as stopping it from melting too quickly. Steve Carrigan explains: “Their job is to reduce fat separation within the mix. Without emulsifiers, the fat would separate and rise to the top, therefore creating an inconsistent mix. The fat has to be even throughout the mix.
Think about old-fashioned bottles of milk where the cream would rise to the top. With ice cream pasturisers the tap is at the bottom, so effectively the mixture would split and you would get a watery milk sorbet at the bottom and the fat would sit at the top.”
The original ice cream emulsifier was egg yolk but emulsifiers commonly used in larger scale production include mono-diglycerides of fatty acids (E471), lactic acid esters (E472b), propyleneglycol esters (E477) and acetic acid esters (E472a).
Contrary to their name, stabilisers are actually thickening agents, which help to influence the viscosity of the ice cream. Made from water-soluble polysaccharide extracted from land or marine plants, they also limit the growth of large ice crystals, which can impede the quality of the ice cream. Other qualities include reducing the risk of shrinkage of the ice cream, improving melting resistance and giving the ice cream stronger stand-up properties.
“If you mix milk and cream together with sugar it will not be much thicker than regular milk,” says Steve. “Stabilisers thicken the mixture which allows you to incorporate more air and therefore makes it lighter. A regular batch freezer will give 35-40% overrun, so three litres of mix containing stabiliser, for example, would produce around five litres of ice cream because the machine would ‘fluff’ it up. No stabiliser would result in less neutral air incorporation.”
The most common stabilisers used are guar gum (E412), locust bean gum (E410), carrageenan (E407) and xanthan gum (E415).
Back to base-ics
Base 50s are pre-made mixes which include emulsifiers and stabilisers. All you need to do is add milk and sugar. The name evolved from the fact that you need to add 50g per litre of milk. The composition of Base 50 is: 5g of stabiliser and emulsifier, 23g skimmed milk powder and 22g dextrose. This handy ready-made mix provides more control and consistency, which is helpful in a busy operation where there are people with different skillsets and experience.
Steve continues: “It’s a great starting point when you are first learning how to make gelato and good for lower-skilled members of your team. However, as you progress, it’s good to experiment and put your own stamp on your gelato. After all, you want yours to stand out and not taste the same as another ice cream parlour in the same town.”
Too much stabiliser will give your ice cream a ‘gummy’ texture.