Recently we recalled juices in three-liter cans - the same ones that many now, I know, remember with sadness.
And there is one in the assortment of these drinks, well, very controversial. Birch juice. He was the cheapest of all - if he bought a glass of this juice in the cafeteria, then it cost, I think, 8 kopecks (7 was a fruit ice cream without chocolate glaze).
The taste of this drink (which was called birch sap) was sweet, with a pleasant, pronounced sourness. Light, spring.
But not everyone believed that this can contained birch sap. And, I must confess, they still do not really believe.
The main argument is how many birches are needed to produce such an amount of juice so that there is enough for the whole country. They say that there was nothing in this drink except water, sugar and citric (and at the same time - ascorbic) acid.
I decided to look for information about birch sap and was faced with the fact that it is more difficult to get it than a military secret. She-she ...
The fact is that its production was not regulated by GOSTs. Even in old ones, those that no longer work (in guests, on juices with sugar, on juices without sugar), nowhere is there a mention of birch sap. There are very interesting options - even lemongrass, but not birch.
There is a technical specification for birch juice, a semi-finished product, the PCT of the RSFSR 537-82, approved by the USSR State Planning Committee, to replace the technical specification from 76, it seems, years. But he regulates the quality of the harvested juice, the rules for storing it before transferring it to production.
And the quality of the finished product - canned birch sap with sugar, was regulated by industry standards, and different - for example, RST of the Ukrainian SSR 1393-75, OST 111-16-84, but the texts of these TUs can be found on the network (and anywhere else, I could not).
I had to go the other way - to look for everything that is more or less connected with the extraction of birch sap and its processing. Luck did not smile at once. First I came across a book by A. In Makarov, "Getting birch sap", already published in 1943. Yes, imagine, in the war.
Canning factories, as such, did not exist then, and the juice was produced by artels. For these artels, the following recipe was given:
After this find, there was hope to find at least some mention of production according to technical conditions. And - it happened!
A pirate (without attribution, alas) published publication "Technique and organization of birch sap extraction" was found on Helpix Org.
And here's a quote from there:
The enterprises of the Ministry of Forestry of the Ukrainian SSR have mastered the production of canned food "Birch sap with sugar" ...
... In accordance with the temporary technological instruction of the Ministry of Food Industry of the Ukrainian SSR, fresh birch sap that meets the requirements of technical conditions is used for canning. …
... The raw materials received for processing are filtered through silk or nylon sieves with a stainless steel shell with holes of 0.5 mm in diameter. Then the juice is loaded into a steam boiler, sugar, citric acid are added, heated to 70-80 ° C, stirring until sugar is completely dissolved, and filtered on filter presses. Before filling into cans, the drink is heated in tubular or plate heaters or in vacuum apparatus up to 70-80 ° С, poured hot into glass jars with a capacity of 0.5-3.0 liters, hermetically sealed with varnished lids and pasteurized. The juice preserved in this way is stored in clean, well-ventilated rooms at a temperature of 0–20 ° C, and a relative humidity of no more than 75%.
So, ladies and gentlemen, what was sold in the USSR under the name "Birch sap with sugar" is birch sap, only with sugar and citric acid.
Another quote:
In 1983 g. only the fruit-processing shop of the Manevich forest farm of the Volyn region. released 151 thousand conditional cans of these products, and in 1984 - about 2.5 million. In total in 1983 canning shops of forestry enterprises produced more than 12 mln. conditional cans in the amount of 2.5 mln. R.
And birches... birches survived. The industrial technology of extraction actually produced a lot of raw materials - much more than we can imagine, occasionally extracting juice in an "amateur" way.