Most of the nations living on the fishery at the sea shores or at the rivers and lakes have their own recipes to preserve roe and caviar for a longer period of time. As there were no refrigerators in the ancient times the only reasonable alternative way to preserve the caviar was salting and drying. The world's most famous caviar products of this kind are the Mediterranian Bottarga and the traditional Russian Payussnaya caviar. Though they are a bit similar in preparation they are different in time and grade of drying.
Unlike the Bottarga where the complete sacs of Mullet roe are first salted, then pressed and after that heavily dried, the Payusnaya (Russian for 'pressed') caviar is made of Sturgeon caviar eggs that are already extracted from the sac. The original and pristine way to obtain the Payusnaya caviar is to take the eggs of the Sturgeon caviar that were damaged during sorting the caviar into grades and packing them into glass jars or tin cans, and the eggs that do no fit the high standards or are too ripe. According to the traditions and standards, the Payusnaya caviar may contain eggs from different species of Sturgeon basically Osetra and Sevruga. Actually, mixing different caviars makes the flavor of the final product even more rich and interesting. After cleaning the eggs from the rest of the sac and other tissues, they are put into a 40°C warm strong brine with pure sea salt just for 1.5-2.5 minutes. After draining the brine, the caviar is placed into the artificial muslin sac for a certain period of time and is hanged to drain. During this stage, the caviar loses up to 35% of the moisture so the external layer of eggs is dried more and getting more intense flavor although the eggs inside the sac are still moist enough. In the end of the process, all the eggs are pressed into a kind of paste reminding a black grainy jam. The traditional recipe of Russian Payusnaya caviar insists on a higher dehydration level, of course not as dry as the Bottarga when you have to grate it over the dish to obtain the requested quantity or cut it like a heavily dried sausage for a sandwich, but the original texture of Payusnaya caviar was rather like a butter. The present tradition allows it to have the consistency that can be either spread on a sandwich or formed in small cubes and added to the cooked dishes like mashed potatoes, rice, risottos, and pasta as a seasoning to transfer the rich and concentrated caviar smell and flavor to the dish. Usually, Payusnaya caviar is not served on its own because of its very intense flavor — sometimes the concentrated Payusnaya caviar may contain three to four times more caviar than the same volume of the regular caviar. Speaking of Payusnaya caviar is not about the look but about the taste!
The Payusnaya caviar is supplied in standard glass jars or tin cans like the other caviars and should be also kept in the refrigerator at low temperatures but due to its preparation method it can last much longer than other caviars so you can enjoy the impressive caviar flavor in your dishes for many weeks and even months after opening it. But are you sure it will stay in your fridge for so long and you will not use it nearly every day to indulge your gastronomical taste?
Speaking about Payusnaya caviar (the Russian for Pressed Caviar) is first of all about the taste and not about the appearance because this product is made of the same fresh high-grade Sturgeon beads as other elite caviars but that were broken during extraction from the egg sac membrane. All beads that were damaged, are too ripe or do not fit the high-grade caviar are mixed and cured with a warm brine for just 1.5-2.5 minutes for the caviar become Malossol. After that, they are put into a muslin sack and pressed to lose excessive moisture down to 40%. The resulting product resembles a jam of a uniform black color with a concentrated caviar flavor that has up to 3 times more beads than the other kinds of caviar.
It can be spread on toasts but more often it is used to add the strong and intense caviar flavor to cooked dishes like pasta, risottos or mashed potatoes.