I know there has been some discussion of boil off percentage with regards to LODO brewing practices. I seem to recall around 5% boil off is the goal. Depending on the starting boil volume 5% can be a very different amount. I brew some 5gal batches and mostly 3gal batches. If I used the same kettle and boil vigor for each batch size I would expect the same amount of boil off. I typically get about 3 liters of boil off in my kettle. For a starting volume of 17 liters that would be 17% boil off. For a starting volume of 28 liters that would be 10.7% boil off.
Should this target be set no matter the beginning boil volume?
Am I thinking way too far into this?
What size batches do you brew and what amount of boil off do you get?
Boil off percentage has little to do with LODO. However, it does have a strong relationship to wort damage and premature staling of the finished beer. While evaporation losses as small as 2% have been cited in technical literature as producing acceptable beer, I question the study and its results. It appears that 6% to 10% is a more practical and workable target for Pro’s and Homebrewers. I regularly limit my evaporation to 8% in a 60 minute boil and don’t have issues with DMS. I was at 17% previously…OK, I didn’t have DMS problems then either…even when brewing 100% pils grists.
Covering your kettle during the initial boil period and reducing your heat input make it possible to reduce evaporation losses and heat stress on your wort. Uncovering your kettle and conducting a modest and open boil for the later stage of your boil is also important. Volcanic boils are not helpful or useful.
I’m giving a comprehensive presentation on exactly this subject this Friday at HomebrewCon in Portland. AHA members should be able to view the presentation in a few months. There is a lot more to this than I’ve mentioned above.
I am interested in seeing/hearing the presentation. I was one who thought boil meant ‘volcano’ and I was around 15% boil off. I now shoot for 8% and have struggled a bit in my effort even at what I’d consider a ‘simmer’. I’ve been hitting 10% but decided to reduce boil times to 45 min in an attempt to further reduce boil off. Plus, I get the added benefit of slightly more volume in the fermenter to ensure I get a full keg in the end.
I take a slight hit in efficiency doing these things but the last couple beers have been noticeable better with this and the additional changes in process (step mash, recirculating, etc), equipment (pump, RIMS, etc), and ingredients (Brewtan B). Maybe bias but I’m digging it so…
My beer is astonishingly improved with gentler treatment these days. I’ve mentioned elsewhere, if you can heat your kettle asymmetrically, you can get rolling circulation with less heat. Efficiency? Saving a buck’s no good if the beer is worse for it. I’m digging it too. Look forward to the eventual release of the presentation.
Well, it was the Low oxygen folks that brought this information forward, and took quite the lickin from folks about it…Glad to see people are slowly coming around. TBI is real (where have I heard that before ).
Nice to see you again, Beerery. What I’ve realized is that even though I didn’t ever self-identify as a LODO partisan, there’s not much daylight between us (especially since I’ve taken to bisulfites in the mash and sparge to complement my very tight cold side practices,) because, apart from a few special procedures, most of what you guys advocate is simply sound, attentive brewing practice. I think the subject of thermal stress is well within that category. Not everyone can pre-boil or spund, but turning the burner down, well … turn it down!
Aim for, sure, but with smaller batches, kettle geometry is going to make this difficult of course. But I’ve come to see evaporation rate as an index of thermal loading, not an end in itself. So reducing the length and intensity of the boil is your goal. It’s just easier to manage not overstressing the wort the bigger the batch, up to commercial scale. Imagine you had only an ounce of wort. Apply any heat at all, and boom, it’s burnt sugar on the kettle surface.
Thanks for the replies. I’ve been stuck on the whole idea of boil off percent. Reducing the boil off by reducing the vigor and keeping the lid on for part of the boil is definitely in my future. I will strive to reduce the boil off as much as possible. I am also changing other parts of my process to reduce oxidation.
I’m also looking forward to Martin’s presentation once it is released.
Yes, the authors Ancient Abbey, Brandon, Techbrau, and Weizenberg (aka - ‘The Team at German Brewing Forum’) and the primary sources they cite, have brought about significant change in the homebrewing community over the last couple years to be sure. It’s a shame they didn’t have a PR guy to soften the blow.
ACTUALLY, the Team at German brewing was those folks AND Steve and Myself, with Brandon and myself assembling said “team”… So cite your sources correct
FWIW, I start with a 7 gallon pre-boil, 60 min low vigor boil (boil off around 8%) and finish with a 6.5 gallon post boil. I transfer 5.5 gallons crystal clear wort into the fermenter leaving behind trub/hops and get 5 gallons into my kegs.
I think you need to change your moniker to “Brewinlowvigor” now. Just kidding, but those are obtainable numbers, for sure - other than the occasional instance where my boil is achieved more quickly than expected and I quickly lower it (electric brewing is so easy to monitor the approach to full boil temp - as long as you watch it!), I am also an adoptee of the low thermal stress approach advocated by Bryan and Brandon and their LOWO2 crew. Adjusting volume to get the right “net into the fermenter” is key.
I will anxiously await the posting of the NHC presentations, as sadly, I will be missing this one in Portland.
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