Caramelisation Effects On Sg

[Shed101]

On a whim I caramelised some of a recent stovetop extract ESB.

I'm guessing it was ~1 litre down to around 330 ml - it was a fluid syrup when added back in to the main pot.

Calculated OG (not accounting for caramelisation) via Ianh's spreadsheet was 1.054.

Measured OG was 1.050

The sample i've been swirling seems all done after 9 days at 1.020 while I was hoping for 1.013 - 16.

So i'm wondering:

Could the OG be lower due to the 'syrup' not being fully dissolved?
(it was in a cube for a week or two before OG reading)

Could the FG be lower due to unfermentable sugars produced in caramelisation?

Yes, hydro reads well normally :lol:

 

[MHB]

Theory says no the SG is determined by the mass in solution, so unless you lost some mass the OG should have been exactly what you thought.
Problem is that there might have been some small losses along the way and the predicted OG of 1.050 could have been just a bit off (we are only talking ~7.4% or 92 grams of extract in 23 litres) mind you that litre of 1.050 wort you boiled contained ~125g of extract so if a lot of it stuck to the pan that could be where your gravity went.

The FG of 1.020 is a more interesting if the 125g of extract you caramelised all became unfermentable that would add ~1.008 to the FG, so if you were expecting ~1.013-16and added 1.008 your FG should be 1.021-24, so the FG is well within bounds. Well less a little bit because the sugar that was caramelised needs to be taken into account I might be punting .001 high.

All up I think you didnt have quite as much extract at the start as you thought you would get, I dont know if this was an AG, Extract or Kit brew so its hard to tell exactly why your OG was a bit low, if you tell us exactly what went into the brew we might be able to pin it down for you.
MHB

 

[Shed101]

Thanks for the input.

It was 21 litres extract with spec grains brew.

All the grains were well steeped and the correct proportion of LDME went in to bring to 1.040 for boil

2600 gm LDME
160 gm Caramunich
90 gm Spec B
50 gm Black Patent
250 gm sugar

(yes ... a bitsa)

Boil volume was 15 ... or 17 litres.