Hello: I am new to the forum and just finished my second all-grain brewing a few days ago. I would like to share a couple of observations and get some feedback from the forum. My first observation is that there was not much evaporation of the wort from the initial boil to completion. Recipes typically have you account for at least a gallon or 2 loss and so have you prepare a pre-boil volume of at least 6.5 - 7 gal of wort for a 5 gallon batch, but I ended up with close to that pre-boil volume even after the boil. Anyone else experienced that? BTW my boil is just a rolling boil, which I what I assume we have to do. Second, this time around I added a Whirflock tablet and some yeast starter; I am not sure if this was the cause of a lot of froth that formed while I was transferring the wort to the fermentation carboy. Looking forward to some feedback from the community.
At what elevation do you live? Can you please clarify what you mean here? Did you make a yeast starter to propagate yeast (i.e., grow up more yeast cells)? If so, when did you pitch your yeast into the primary? Cheers!
Did you actually measure the pre-boil volume? Also, keep in mind that hops (and anything else) adding during the boil increase the total volume. And at boiling temps, the volume is actually larger, compared to what it will be after cooling. The best way to get a handle on your actual boil off rate is to boil a measured amount of water for some amount of time (say 30 minutes), let it cool, and measure again. Double the decrease in volume and you'll have a good estimate of your hourly boil off.
Whirfloc and yeast nutrients can cause a tiny amount of foaming when added to the boil. But they wouldn't have caused the foaming you saw when transferring. That would have been caused mainly by proteins in the wort, the same kind that cause foam when you pour a beer. Note: it's not a bad idea to transfer gently and avoid the foaming. Those foam positive proteins are "single use only."
Another aspect that can impact the evaporation rate is the amount of surface area. A kettle that is more 'squat' will yield a greater surface area and an increased evaporation rate. The 'challenge' of the description of "rolling boil" is that it is subjective. What I consider to be a 'good' rolling boil may be more robust than what you think is a 'good' rolling boil. One of the benefits of maintaining a 'good' boil is that it encourages volatization (drive off unwanted aromas). One example is driving off SMN (the precursor of DMS). If you are not experiencing any off-flavors in your resulting beer your boiling is 'working'. Just be aware of the evaporation rate in your homebrewery to account for the proper volume going into your primary. Cheers!
What is your heat source and what kind of kettle are you using? I am going to guess that your idea of a good rolling boil might not be exactly the same as my idea of a good rolling boil. Because, water boils at the same temperature, all things being equal. And even when all things are not equal water still boils at pretty much the same temperature. So your observations have a real explanation and it's not that textbook instructions are wildly miscalculated. The difference is the in the kettle shape and the amount of heat applied. So, if you are using an electric stove or a your kettle is tall and narrow, then you are not getting a real good boil. Cheers
what it says to me; the 2nd batch has not yet been 'dialed in' to the system there's a learning curve ... hang in there consult your notes adjust the pre-boil volume or the boil's duration and try again ...
You bring up a good point. My kettle is tall and narrow and I applied enough heat so I could watch the wort on top rolling over gently...I know this is subjective but do not know how else to describe it...I used a heavy duty Blichmann Hellfire so I could definitely crank up the heat if needed..so how else should I judge whether I am getting a good boil or not?
If it's actually rolling, it's good. There is no need for a "jumping" boil. They key is to measure the rate so that you can use the right amount of water to hit your intended post-boil volumes.
I use a Robobrew, which is also tall and narrow (12" diameter) and a bit underpowered. My boil-off is only about 0.6 gal/hr.
I am going back to what Vikeman mention, fill up your kettle with about 5 gallons, get it boiling and let it boil for an hour. Stop, chill to room temp, and know your boil off rate after measuring again.
to a 1st approximation; try measuring the post-boil volume ... reduce it by 4% ... and be done with it
