This idea of using extract was discussed not that long ago. Considering I use only 100% maris otter or golden promise, it makes sense to me. The only downside I see is a little extra cost.
Boiling down the first bit is 100% worth it in my opinion. I build the recipe around the extra volume loss.
The scottish 80/- I recently brewed was simply 10lbs of mo and I aimed at 8.5 gallons starting volume. After adding the reduced volume back, I was just shy of my normal post boil
I’ve been using my camping stove to perform the reduction so I can keep an eye on it.
I boiled down until I had a nice thick syrupy thing that was extremely sweet and caramely and would foam up the entire stock pot if left. Coated a spoon with a nice, sticky, thick layer, too. Steam was still boiling off, the temp never went above 212°F, and it measured out to be 1 qt.
So I didn’t take it up to the soft ball stage or anything, or boil it down to a pint, but it still became about what seemed right. I could have taken it further but that’d require moving it to a smaller pot to get an accurate temperature reading and that’s a whole bunch of syrupy mess!
I believe the original recipe (a la Skotrat) was to boil one gallon of first runnings down to one pint This is what I usually do and you get an awesomely thick, sweet syrup. Never measured the temp though. And the beer is always wonderful.
I brew in my kitchen, so I have my main boil going in a 5-gallon kettle on one burner and my side boil going in a 2-gallon pot on another burner. In my experience, the side boil is generally ready about halfway through my main boil, give or take.
It depends on heat and kettle geometry. I do my kettle karma in my 15 gallon BK so it’s on flame and about an inch and a half deep. It takes about the amount of time it takes for my sparge water to reach 170. Then I finish running off the mash, do the sparge, and ba bing
Here’s a data point. I just did this last night with some cider. It took almost exactly 2 hours to get 1.5 gallons of 1.048 cider down to the right consistency in a 2-gallon pot on my glass cooktop. One gallon of heavier runnings will take less than that.
One other thing of note - watch it very carefully (especially near the end). I walked away from the pot for 10 minutes with what I thought was still quite a bit of liquid to go. When I walked back the bubbles were almost out the top of the pot and it was down to a pint and a half of syrup.
(Random side note - apple cider syrup is every bit as delicious as it sounds)
Yes, Cider syrup is delicious. My friend just partnered with a cider maker and they bought a huge evaporator and sell it: Products | carr's ciderhouse. I’m thinking of slipping some into a beer but not sure what style I want it in. BTW the evaporator is a good model for reducing the runnings fast with less energy input: use as wide a thick bottomed pot as you have.
While we’re talking practice, I kill the heat on the side boil, then I ladle in a pint or two of the main boil to cool/thin/deglaze the syrup. Does anyone else do this, or are you just dumping it right into the main boil? Also, I just add it to the boil whenever it’s ready, rather than waiting until the end.