I was told that you can get in the ballpark on 5 gallon recipes (and all grain after calculation) by simply dividing by 5. How true is this? How big is the ballpark?
Pretty close but you boil off volume is going to be the same regardless of how big your batch size is. Hop utilization will be a bit better because you’re going to have a smaller average extract concentration but probably not enough to make a difference in most recipes.
Can you elaborate on the boil off volume comment?
If you normally lose a gallon an hour with a 5 gallon batch, you will lose a gallon an hour for a 1 gallon batch on the same system. Ingredients can be cut by 1/5, but your boil volume should be (target final volume + boiloff) and not 1/5 of a 5 gallon batch’s boil volume.
So 2 gallons?
I depends on a number of things I think. How aggressive you boil, humidity, kettle shape and surface area…
You can start with 2 gallons and adjust from there. Keep some pre-boiled water on hand incase your boil off is greater than expected.
If boiling indoors, kettle shape and how vigorous a boil will be the main factors.
Also, if you are fermenting in 1 gallon jugs, you will want less than 1 gallon when finished.
For smaller batches (1 and 5 gallon) how much will too much or too little water make a difference on the final product? In extract batches (my case) I normally will add top off if it is low.
Is the point to ensure the least amount of top off water necessary, therefore boiling the majority of the volume?
The main reason to avoid topping off is hop utilization. Hop utilization is lower in higher gravity wort.
I top off my 10 gallon batches because my keggle is only about 12.5 gallons (50 liter European keg) and I want my pre-boil to be about 13.2-13.5 gallons. I normally add 1.5, but sometimes 2 gallons.
+1. Full wort boil any time possible.
So you boil MORE than your end volume (mind blown) ?
My preboil is 11.7 gallons. After 90 minutes I have 10 gallons in the kettle. I add 1.5 gallons of preboiled water to the kettle at flameout (I boil while mashing and leave to the side with the lid on). I transfer to two fermenters, roughly 5.5 gallons each, leaving .5 gallon in the keg.
Ideally, my keggle would be large enough for a 13.2 gallon preboil. I lust for a 20 gallon blichmann kettle, but any decent quality kettle would do.
I boil ~48 liters for a 40 liter batch of strong beer. In a 50 liter kettle it can get exciting at times
Correct. That may be something new to you if you’re used to topping off, but it’s standard practice when you’re doing full-volume boils. Depending on your kettle size/shape and how strong your boil is, plan on boiling off about 1/2 to one gallon in an hour.
And you can always top off if you overshoot and end up with less volume than you’re targeting.
I hear ya. I start with just under 4.5 gallons in my 5 gallon kettle. And I need to leave the lid on to be able to reach a rolling boil at that volume. Thank goodness for Fermcap.
There are several calculators out there that will help you with this. Boil off time is the time it takes for the water to evaporate or how much is evaporated over a period of time.
What I did, was Put in 1 Gallon of water in my pot. I then Took a Yardstick or ruler, dipped it in the pot and measure the water.
I then went to the calculator and put the diameter of the pot and how deep it was and then I put in Inches how much water I had.
Then I boiled for 15 minutes. I measured the water again with the ruler or yardstick I input that number.
Calculated it and it told me what my Boil off was. You can do 15 minutes times 4 I think it is, or 30 minutes time 2, and so on. I just did the 15 minutes.
All in all you need to know how much water evaporates during your boil time because you’ll need to add that in the pot before you start the boil so you can anticipate how much water you’ll need. And if I recall, I think it’s around 1 to 2 quarts (Half Gallon) you’ll need on average.
So with a 1 Gallon recipe (IF IT’S NOT ALL GRAIN), you’ll need around 1.5 gallons of water for a 1-gallon batch.
If it’s an All Grain batch, you’ll need half a gallon for boil off. Then you’ll need around 1.5 quarts per 1lb of grain you use for a 1-gallon batch.