Isinglass: the animal-derived gelatine
75% of creamy desserts and spoon desserts recipes contain an ingredient that allows us to
thicken our creams: I am talking about “isinglass”, or fish glue, which is commonly called
To be honest, I never fancied the name “fish glue”, because the combination of sweets and fish
is a horrible match indeed!
Although it is no longer produced with fish swim bladders or cartilages, and fatty pork (80%) and
cattle tissues are used instead, the term “fish glue” is still commonly used.
From a visual, olfactory and gustatory viewpoint it is odourless, tasteless and colourless.
Its melting point is around 35°C, which is lower than the temperature of the human body: this is
the reason why gelatine becomes fluid when it hits the warmth of our mouth.
Other thickening agents don’t, making isinglass hardly replaceable in some recipes.
Let’s have a look together at the most common types of gelatine.
Fish Glue in Sheets
Sheet gelatine is practical and readily available in both bakery products wholesales and supermarkets.
Isinglass, the animal-derived gelatine
On the market we find 3 types of isinglass in sheets:
BRONZE – 130 Bloom
SILVER – 160 Bloom
GOLD – 200 Bloom
The term “Bloom” refers to the setting strength of the gelatine.
The rule you should never overlook is to weigh ingredients bearing in mind the gelatine
Here is an example of quantities with the same thickening strength:
• 15.4 g bronze gelatine 130 Bloom are equivalent to
• 12.5 g silver gelatine 160 Bloom that are equivalent to
• 10 g gold gelatine 200 Bloom that in turn are equivalent to
• 8.3 g gelatine 240 Bloom.
These gelatines differ in weight and thickness.
Professional sheets usually weigh 4-5 g each, while those for home use weigh 2 g.
Since gelatine is a dry product you must always hydrate it in cold water before using it.
How to Hydrate Gelatine – Two Methods:
- Sheets are soaked in abundant cold water, squeezed and added to a warm liquid or dissolved in a microwave. With this method, however, pieces of gelatine can be lost and you risk ending up with a smaller amount of gelatine in your preparation.
- Sheets are weighted (1/6) and added to a weighted cold water (5/6). Water must be 5 times the weight of the gelatine (e.g.: 5 g of gelatine + 25 g of water = 30 g, that is 6/6).
- The gelatine sheets are added in pieces so that all the pieces come into contact with the liquid. Once softened, the gelatine can be easily dissolved in hot preparations or microwave-heated.
The amount of gelatine you need depends on the final consistency you wish for your dessert:
20 g of gold gelatine sheets can gel 1 l of water to a soft, spoonable consistency.
40 g of gold gelatine sheets can gel 1 l of water to a firm, cutting consistency.
Do not forget:
• Gelatine must be perfectly softened before use
• It can never be used without being hydrated with water first (unless it is a “fast”
• It does not dissolve in cold liquids
• If salts or acids are present, consistency problems can occur
• Setting properties can be slightly reduced by negative temperatures
Also this gelatine must be hydrated in 5 times its weight of water; 1g is equivalent to 1g of fish-glue in sheets.
Powder gelatine (similar in appearance to cane sugar), is 200 Bloom and must be hydrated.
The quick setting gelatine type (also “fast gel”) is 170 Bloom and it starts dissolving at 30°C
(neither pre-mix nor hydration are required).
As I mentioned previously, I recommend buying gelatine with its Bloom indicated in the product
Soon I will write about plant-based alternatives to gelatine sheets, such as:
Agar-agar, carrageenan and pectin.
Powdered isinglass, i.e. Animal-derived gelatine
Have a nice dessert!