I have a few pounds of turbinado sugar I may try this with using the oven this weekend. I will make sure to check the oven’s calibration first. Jeff just mentioned leaving the cover of the Dutch oven on. Evaporation isn’t wanted/ needed I take it?
The water has evaporated. My thoughts are that the lid helps even the temperature as the stove oven cycles on/off/on. The measurement was dead on 240F, which was satisfying to see.
The feature of this technique is that your work storing the sugar syrup is done once you put the Dutch oven into the stove oven. Set the timer and go do something else.
Regarding evaporation don’t worry about it. Trust the process. If you start with a pound of sugar you will end up with a pound of invert. I really should use the oven method but I make mine on the stove top with a candy thermometer and just baby sit the hell out of it until it is finished. That’s 2 1/2 hours or more of not leaving the kitchen to make a batch of #3 so I always do at least 5lbs at a time.
I’ve used a stove top pressure canner (a small 12 quart one) to help make invert sugar and regulate the temperature.
I start the sugar, water, and acid on a normal pot on the stove to get up the syrup to 240 degrees. I then transferred the invert syrup into pint mason jars (which has ended up being about a pound a piece), add those to the canner, and let the pressure canner come up to pressure and ~250 degrees. It’s easy to keep it there for anywhere from 20 minutes to a couple of hours depending on which grade I’m making. It worked pretty well and gives me nicely portioned amounts in sealed containers. I may make a bunch of cup jars next time for extra flexibility.
I’ve also made small batches of invert #1 this way when I’ve also needed to can some wort for yeast starters. Increase the pressure time to whatever you need and you get some sterilized wort and lighter invert sugar at the same time.
Mike
This post has the recipe from Ron Pattinson that Kevin refers to above.
https://www.homebrewersassociation.org/forum/index.php?topic=31756.0
An invert sugar accident…
I’ve made invert sugar a number of times. One of the last times I moved it to a glass jar in the sink to allow it to cool. After a bit I wanted to check the weight, but unfortunately I hadn’t given it enough time. As I was lowering the jar onto the scale, the bottom of it gave out. You can see in the picture that the bottom of the jar landed right on the scale. I would estimate there was probably 4 - 4.5 lb of invert sugar in that jar, and it was all over. That is one of the worst cleanups I’ve ever had.
In regard to making invert sugar, I’ve always followed Ron’s guidelines.
That’s brutal!
I am glad you were not hurt, hot syrup and shards of glass would not have been good.
But the beer was ok!
Lol! Yep, the beer survived. And I finished that beer on the porch in a state of disbelief before I started cleaning stuff up.
Any opinions on what the most useful invert sugar is to make and have around for multiple recipes? I haven’t paid attention to how often various invert varieties appear in recipes.
For me it is invert #3. It will probably depend on what recipes you make the most. Invert #2 is called for only occasionally. Recipes (that catch my interest) requiring #1 are rare and I have never found a need for #4.
During this whole conversation I completely forgot that invert sugar is available in the US. For the longest time brewers on this side of the Atlantic had to make our own as discussed but fairly recently a company called Becker’s began producing invert #1 #2 and #3. Right now it is only sold at Adventures in Homebrewing but it is out there. The reason I forgot about it is that it is damned expensive imho. But for some it may be worth it to not have to stand over the stove for 2.5+ hours.
Matt Becker is a friend from my Homebrew Club and I enjoy his beers and Brewery in Brighton MI.
Pricing is set by Adventures, same as the Belgian Candi Sugars. You now can buy it by the pound vs 3 lbs.
I would agree #3 for most British styles… In Ron Pattinson’s book of Homebrew recipes one Bitter recipe is pointed out as being unusual for using #3. Most use #1 for a Bitter.
For anyone with a spare 20 minutes, this has to be the best, funniest, most “real” video about making #1 (golden syrup).
OK, this has me sold. Taking over the kitchen for brewing beer every few weeks is a tough enough sell to the wife as it is. If I can throw this in the Instant Pot for a few hours, then I might be able to get away with this 
My side was hurting from laughing watching that! That is not what I experienced.
:) Not my experiences either, but it was watching this that convinced me even I could make #1!
Some areas around here have a fair amount of British expats here with the Auto industry, so i see Golden Syrup if i go to stores in those towns.
Going to make my own for a Bitter.
Keep in mind that golden syrup and invert are not entirely the same thing. Commercial brewers in England would almost never use golden syrup. Golden syrup has become a hack for homebrewers who cannot get proper invert sugars. The flavor profiles are very different. @Northern_Brewer has written often about the differences at homebrewtalk .com.