Indeed, gelato-makers everywhere should be looking to investigate it thoroughly from a chemical and physical point of view, as this is the very heart of their product, and is responsible for many of the sensory effects and the versatility that make gelato so appealing.
It is well known that changing from one base to another is a delicate issue in gelato making, because it affects the balances that will impact the structure, flavour, creaminess, stability and overall performance of the gelato at all stages, whether that be in the display case, during storage or in the cone.
In this article, we will be focusing on the macroscopic differences between bases of different weights, how they can be used and the advantages/disadvantages of using each one. So we won't be getting into the heart of the matter, i.e. how to read the label on a gelato base, break it down into its component parts and re-balance it to meet our needs, an issue that involves several mathematical processes, as well as solid experience which needs to be built up through proper groundwork and training.
Gelato bases can be divided into two main categories – bases for fruit gelato as against bases for dairy gelatos. There are, however, also some so-called hybrid or universal bases, but they are of little interest in countries where gelato is taken seriously.
Fruit bases are semi-finished products that usually contain no fat and dairy derivatives, given that the traditional Italian sorbet is a mixture of water, fruit, sugars and stabilisers. Their composition is therefore relatively simple although they are more complex in the hydrocolloid phase (stabilisers) and, in some cases, in the emulsifiers which, in the absence of fat, serve to stabilise sorbet overrun. Cream bases are far more complex and varied, their composition and weight ranging from everyday convenience bases to highly technical products. Moreover, gelato itself is an extremely complex foodstuff that has to combine phases within itself that are incompatible in the natural state – indeed, it is stored at very negative temperatures but usually consumed at temperatures well above zero.
The forefather of bases, already found in some recipe books from a couple of centuries ago, is the neutral base, a mixture of emulsifiers and stabilisers, usually in a 60:40 ratio. The quantity of neutral base used for a dairy gelato varies from about 0.4 to 0.6 % of the total mixture. That means that 60 kg of total pasteurised gelato will contain 240 to 360 grammes of neutral base.
In fruit-flavoured gelato, most industrial-type neutral bases are emulsifier-free and are made up only of preferably acid-resistant hydrocolloids, so the amount goes down to 0.3 to 0.4 % of the total mixture. With fruit sorbets, given that the typical unit of measurement is the cold-prepared tub (let's say a 3.7 kg tub), this adds up to about 11 to 14 grams of stabiliser added to the total mixture.
I presume it is clear that precision when dosing the neutral base is paramount. The difference between an 11 gram and a 14 gram dose is about 25%, and this small, at first sight seemingly insignificant difference radically changes the rheology of the finished product, i.e. the behaviour of the gelato's “fluid” structure, to the extent that it will become “chilly” and icy on the palate when under-dosed, or sticky and shiny when over-dosed.
Another consideration, especially in fruit-based emulsifier-free neutral bases, is how well the neutral base binds water from the surrounding environment during storage.
Being a hygroscopic product (i.e. tending to absorb water easily), bearing in mind that the shelf life of a sachet (or even worse a bag) in a gelato parlour needs to be quite prolonged given the low dosage used, and that the gelato parlour is in itself an environment with a rather high relative humidity (given the various pasteurisers and condensers etc.), the neutral base will lose some of its functionality day after day, once the hermetically sealed pack has been opened. Indeed, manufacturers carefully check the residual activity of neutral bases before using them in mixing processes, recalibrating their proportions if necessary or using suitable higher viscosity ingredients.
It is therefore understandable how the end result of gelato made with a neutral base can vary so much: on the one hand, the dosages need to be almost pharmaceutical in their precision, often without the right equipment; on the other hand, the product undergoes spontaneous variations during storage, especially in the summer months, a phenomenon that is almost impossible for the gelato-maker to control.
The advantage of using industrial neutral bases, however, is that they are inexpensive to use, which is why they are often favoured by industry rather than by artisans. It remains clear, however, that when looking for an inexpensive recipe for a specific market or sales segment, a neutral base is still a product that carries with it greater risk in terms of the quality of the finished gelato, requiring large production volumes for rapid product turnover, as well as careful handling, especially when it comes to small production outlets (by which we mean the normal amounts pasteurised in the average gelato parlour).
In the case of dairy-based neutral bases, the issue of variable viscosity has partly been solved by encapsulating the hydrocolloids in the emulsifying phase, a lipid phase which is therefore “protective” for water. In practice, the hydrocolloids are dispersed in the emulsifying phase, transformed into a liquid state, thoroughly mixed, then brought back to a solid state, refined and reduced to a somewhat granular and powdery state. This favours stability at relative humidity while reducing the solubilisation of the product at temperatures below the melting point of the emulsifier, usually above 62°C.
The next step after industrial neutral bases, in the gelato industry, are the so-called bases, i.e. semi-finished products that add a certain degree of convenience or technology to the neutral base/emulsifier mix. In the past, the first bases were neutral bases with the addition of dextrose and/or powdered milk, preferably low-fat. When bases were first being developed, it was far from easy to source these two ingredients which were used to give positive properties to gelatos that were often made in a rather unsophisticated way, with few to no dairy solids or monosaccharide sugars. This is what I mean by providing the gelato maker with a bit of convenience, i.e. enhancing to a core stage with ingredients that will lead to improvements but which can still be found on the raw material market in reasonable quantities for a small operator.
Most fruit bases still perform this function, which is to make the dosage reasonable for a gelato parlour, to stabilise and "protect" the hydrophilic phase of the mixture, and to ensure that it is properly dispersed during hydration, avoiding the formation of lumps that are hard to dissolve.
The optimum use of a neutral base in the gelato parlour requires the use of structure supplements based on dairy/whey proteins, vegetable fibres or pre-emulsified fats. These products make up 0.5-2.0% of the ingredients, thus compensating for the rather 'simple' structure yielded by the neutral base, bringing the creaminess and palatability of an industrial-like product up towards the typical quality of a hand-made gelato.
The recommended dose of this second round of bases is 3.5%, i.e. about 50 grams per litre of liquid phase, whether that is milk, water, or water and juice (in the case of sorbets). In the case of fruit stabilisers, the standard 50 grams per litre dosage helps to maintain constant quality of the finished product, while in the case of dairy bases it performs far more crucial functions, such as supporting the stabilising and emulsifying phase of the neutral base and sometimes even stabilising the flavouring of fior di latte. We thus begin to see a base made up of building blocks, one of which is the stabilising and emulsifying part, one, if present, the flavouring part, one the “binding” phase, consisting of dairy or whey proteins and/or vegetable fibres, one part made up of carbohydrates, normally mono saccharides or poly saccharides and, in some cases, a creaming or aerating fat phase.
In Italy, the average dosage for bases is 50 grams per litre in the case of fruit bases and somewhat less in the case of dairy products. They are without doubt technical products, making up some 8-9% of the total solids in fior di latte, so the gelato maker needs to be very familiar with their composition in order to make it easier to achieve a balance. In the case of fruit bases, they are cold-processed (or hot-processed, although hot is no great advantage over cold), while dairy products can be either hot or cold-processed. In this case, the optimal process, if using the base from cold, will depend on the other ingredients used in the recipe.
A 50 g/L base can reward the experienced gelato maker, but does not allow semi-finished product manufacturers to make the most of the technological possibilities currently available to them. Indeed, it is complex to create 50 g/L clean-label bases, for example, or ones with special stability properties such as might be required by a gelato produced for sale to third parties, and therefore where there are issues relating to transport and compliance with the cold chain. In this case, they are best suited for use in combination with structure supplements – just like neutral bases, albeit at lower percentages because they are normally already incorporated in the bases.
The range of bases that is best suited to bringing together semi-finished product manufacturers and professional gelato makers is 100 grams per litre of milk, which extrapolating from the above results gives us around 7% of the total mixture. These bases, normally the most popular in the dairy segment, are rather complex mixtures of functional ingredients, which may be enhanced with sugars such as glucose syrup or maltodextrins.
Again, the main difference lies in the solubility, which can be either hot- or cold-processed, and in this case the amount of soluble solids provided by the base may be enough to balance the finished gelato (albeit minimally) in terms of solids that are normally insoluble when cold. The use of pre-emulsified fats, dairy proteins instead of milk powder, cold-soluble hydrocolloids and so on make it possible to work quickly and efficiently, e.g. for emergency production or testing new flavours or quick comparisons between two or more bases.
Even in this case, the 100 g/L base can be seen in terms of building blocks, just like the 50 g/L base, but in this case the preponderance of the building blocks in the mixture is more significant and the practitioner's knowledge of their own base is essential to achieving optimum quality.
In addition to the 100 gram per litre bases, there are so-called high grammage bases, normally divided into 150 grams per litre (10% use), 200 grams per litre, 250 grams per litre, and even up to 500 grams per litre of water, or water and milk (33% use).
Some of the bases that have made a name for gelato parlours both in Italy and elsewhere fall into the category of high grammage bases that combine technological input with an ever-increasing amount of convenience, helping to reduce the degree of error on the part of the gelato maker, simplifying the supply chain and speeding up production. Normally, these semi-finished products are for the dairy category and not for sorbets, although it is not uncommon to find unflavoured products listed even for fruit sorbets (to which water and fresh fruit are normally added) in the offerings of semi-finished product companies.
To conclude this quick overview of gelato bases of different weights, it should not be forgotten that there may be intermediate products, but they still fall into the above categories. Knowledge of the composition of the bases, which can be interpolated from the ingredient list and nutritional information on the packaging, is a key part of the gelato maker's professional expertise. In addition to this, a sound knowledge of the raw materials and additives used to make the base helps the artisan choose the right base for the requirements of the business and all its characteristics.