Bearing in mind the title.... I'm confused and hoping someone will summarise thusly:
"To make invert sugar, do <insert method>... "
My task of running up 10,000 hits to my original (off-site) thread has passed. Together with associated controversy (I hope). So, I'll replicate the instructions here. It's a very simple method! Because ... there is no need for the task to be difficult! These methods were to replicate the historical products (such as often specified in recipes dusted off by Ron Pattinson).
BASE SUGAR
I used Billington's "Golden Castor Sugar" and/or "Dextrose" (aka. glucose or "corn sugar"). I used all dextrose as base or 20% of total (like Ragus) ... it ferments easier and quicker but
may have unknown implications?
You could use ordinary granulated white sugar, or, if you must, even baker's clear invert syrup, or make your own neutral invert syrup base. Don't use Golden Syrup, it's quite noticeably caramelised (and some people won't like it!).
This "base" is only fermentables, we get on to flavours next (the key was
subtle use of flavoured sugars).
FLAVOURING SUGAR
(As a percentage of total sugar. If using a syrup as "base" make allowance for water content).
Using Billington's "Light Muscovado Sugar". Demerara, Molasses syrup, black treacle, "generic" brown sugar, etc. were found to be too variable to use predictably. I personally tested these using the lower figure in the range (sugar purchased mid 2022, though I wouldn't worry too much about manufacturer variations).
"Invert Sugar No.1" ... 12 - 15% Light Muscovado Sugar
"Invert Sugar No.2" ... 24 - 30% Light Muscovado Sugar
"Invert Sugar No.3" ... 48 - 60% Light Muscovado Sugar*
* Billington's "
Dark Muscovado Sugar" preferred; see next.
"Invert Sugar No.3" ... 17 - 20% Dark Muscovado Sugar
"Invert Sugar No.4" ... 85 - 90% Dark Muscovado Sugar
For historical recreations: You can probably avoid "Invert Sugar No.4". It was rarely used, and the above formulation is probably too "nice" (the reality was it was by far the "roughest" of these sugars used). I used 60% Billington's "Molasses Sugar" in the trials for "No.4", but that sugar is less easy to find.
Footnote: "Invert Syrups" were created for convenience. It allowed higher concentrations of sugar. At a time when transport was a little more difficult. (Syrups containing only 60% of un-inverted sucrose sugar would crystalise - a right pain if using barrels for transport). However, some claim to be able to tell the difference, so going to the trouble of "inverting" is left up to the individual. Ragus (the last remaining manufacturer of Brewer's Invert Sugar) do use inverted syrup, which may be a marketing decision, or they do think it makes a difference flavourwise?
Most breweries these days use sucrose or glucose syrups, not invert.
There was (historically) strict tax rule applied to UK brewers' concerning sugar and the types allowed. Hence the UK developed very different ideas to sugar than the rest of the world.
The old (19th C.) method of making Invert Sugar and sugar refining has long ceased to be. Hence Ragus use a method of flavouring neutral invert syrup with molasses syrups much like the method detailed above! Ragus also add 20% powdered dextrose (glucose) to trigger crystallisation of the Invert Syrup (these days it is more convenient to pack it in boxes as a solid).
The neutral invert syrup can be made from beet sugar! It is chemically the same as cane sugar and no longer harbours unpleasant flavours like beet sugar of old.
I choose to use Billington's sugars because they are readily available in the UK and some other parts of the world. But I've chosen to use "Muscovado" sugar because an equivalent product should be available in other locations.
The method was modelled, and tested against, the Ragus Brewer's Invert Sugar, types L, M and D (they don't refer to the numbers or replicate the - rough-as-a-badger's-bu*, err, allegedly - "No.4".