MtRainier wrote:...Could I increase the botanical bill, steep in 43%, then dilute down to 10% after filtering and run it?... I know I’ll lose some flavors into the extra water, but would I need to increase the botanicals by a factor of 4 to take into account the extra dilution or should I just try to run a bigger batch to fit my boiler?
Let’s see.... 3 gallon charge at 43%ABV would have approximately 3 x .43 = 1.29 gallons of alcohol (potential).
Now, if you removed the alcohol alone, that would leave you... 3 - 1.29 = 1.71 gallons of water (backset) in the boiler.
But bear in mind that you won’t pull the alcohol out pure, more like 70-80%ABV. So, the amount of the charge pulled would be.... 1.29 / 0.75 (average) = 1.72 gallons.
That would only leave you... 3 - 1.72 = 1.28 gallons in the boiler. Therefore, you’d need to stop before you got it all out. You’ll leave some of your gin in the backset.
Now, suppose you dilute the maceration to 30%ABV, then you’d have a (potential) alcohol charge of... 3 x 0.30 = 0.9 gallons.
But again, you won’t collect the product at 100%, more like 60-70%ABV.
So, the collected volume would be... 0.9 / .65 (average) = 1.38 gallons. And that would leave... 3 - 1.38 = 1.62 gallons of backset in the boiler.
So, if you dilute to 30%ABV to run, you should be able to run without “dry firing” your boiler. But the product off still will be a slightly lower purity. And the additional dilution will reduce the flavor profile somewhat. But you should still be able to produce a drinkable gin.
The limiting factor of your boiler is the necessary charge size to keep the element covered. As a result, you must learn how to do the math and then pay attention to the product (volumes) to keep from dry firing your element. When things are this close...it gets tricky. So you’ll have to learn your system and how to use it safely.
Good luck. Be safe, responsible, and discrete.
ss