This is getting to be my most frustrating issue with brewing. I’ve been having a terrible time attaining a repeatable boil off rate. As you can imagine, this means my OG levels float about ±.005.
Consistent boil off seems to be a moving target as well…I’ve tried making a mark on my gas regulator and always boiling at that point…but the weather and propane levels seem to be other variables.
What is everyone else doing about this?
I boil to gravity, not time or volume so my gravity is right on the money. Although that means that sometimes my volume is off. I’m just starting to play with an induction plate. That may give more consistent results.
What do you do about hop timing then?
I’ve (finally) learned the lesson to brew a larger batch size than I’ll ever ferment, that’s eliminated any dead space/volume issues.
I take a gravity reading at about what I estimate to be 20 min. to end of boil. If I’m where I expect to be, I go ahead with hops. If not, I boil longer before I start the finish hopping.
I inspect the “quality” of the boil rather than looking at gas settings. I’m looking for good turnover and some bubbling. I tend to boil to volume so I go a little longer if necessary or add water. I often check the volume with 20 minutes to go which is about the earliest that I’ll add hops after the bittering addition.
I don’t have an opinion about the pros and cons of boiling to volume vs to gravity other than measuring volume is easier for me. Generally if I hit my volume, I’m pretty close to hitting my target gravity.
Same for me, I boil to volume. But I measure my strike water down to the oz and know my dead space and boiloff rate pretty accurately, so if I hit my target volume then I’m usually within a point or two of target OG. Except for a couple German maltsters like Avangard and the Barke malts where extraction is higher than most - had to learn to account for that.
As proven in Brulosophy exbeeriments and by beer machines like Picobrew , you don’t have to have a vigorous boil nor have your kettle uncovered to produce great beer. Evaporation losses are driven by the exchange with the atmosphere. If you partially cover your kettle, you will be able to better manage your evap losses.
Boiloff rate truly is a little bit variable. When I have 20-30 minutes left in the boil, I check the volume and how close it is to what I expected. If too low then I consider whether to add more water to allow a longer boil or whether to start adding my late hops right away and shorten the boil. And vice-versa, sometimes I have to plan for a longer boil. In either case it doesn’t affect the bittering significantly in most cases, but could affect timing of the late hops.
Humidity makes a big difference in my boiloff rate. Personally, I’m pretty laid back about hitting my numbers. If I’m off by too much, then I just add some DME at the end if the boil, but normally I just let it ride.
With no good way to measure volume, (long story) I guess I’ll just accept my numbers being off.
Which has never been a big deal for me, was just curious if there was an easy way to resolve this. On the plus side, I’ve got new requirements for whenever I again redo my brewery…
Phil, I use a cheap piece of wooden dowel rod to measure kettle volume. I add water in increments and make a sharpie mark on the rod at every interval. Ends up looking like a long round ruler but it helps me keep volumes spot on. Cheap 'n easy.
The issue is my brewing surface is far from level, and I don’t always set it up in exactly the same spot. Realistically, I can get the volume by measuring several different places around the kettle and doing some math, but it’s too much of a pain. Better just to be close to my target for now.
I always measure from the center on the kettle, I think that gives me a consistent volume reference point as my stone patio is far from level as well. Does anyone account for the temperature of boiling wort in the measurements? Or is it really not significant?
-Tony
With all this talk aboot boil volume, how do guys account for volume changing after chilling ie expansion/contraction.
I measure from the center point, too. I account somewhat for temp. The wort at the end of the boil will supposedly shrink in volume by ~ 4% by the time it’s cooled, so since I target 5.5 gallons post boil, I try to have ~ 5.75 gallons at flameout. I don’t really obsess over it either, though.
Mostly tears and regret.
But seriously, I just have some marks that I hammered into the side of the kettle at the gallon marks so I can look and see. I put them on 2 sides so I can average if things are crooked.
All in all, I don’t worry about a couple points. I doubt that most people could taste the difference in a modest difference (2 or 3 gravity points) in most normal strength beers.
+1 here. Had to do it yesterday in fact when I undershot OG by over sparging. I also noticed a big swing in boil off rate my last few brews, now that the temperature is lower along with the humidity (Vermont)
I boil inside in my brewery which is always 66f and 34% humitidy(it has its own thermostat/huminidfier). I also use a special cut lid, and the same pid power on my element every time. 99 brews out of 100 I am within 2oz of volume and sub 1 sg point. So it is possible. Just takes some work!
Yeah, my old electric system that I used in the garage had no issues with repeatable boils. But it was out of the wind, and at least partially climate controlled…but lack of a decent ventilation meant it got damp…and the damp was bad for the car tools, let alone the structure.