Begs the question, does an AIO system materially shorten a brew day? I don't know.
Can envision convenience on a few fronts but not so sure I'm envisioning a significant time savings.
Might get more responses to that point if you can change the title to reflect the underlying question.
Maybe like, "Did an AIO system materially shorten your brew day?"
Good point. I do a lot of equipment reviews, so bounce around a fair amount between different brew rig set-ups. I've done several AIO units, as well as brewed a lot on my 2V/3V RIMS setup. I have not found AIO to make a brew day faster. But there are a lot of footnotes that go along with that. I would say my typical brew time is 5 hours from mash-in to cleanup done. Across all of my systems. But here are the footnotes with respect to time:
1. The ability to preheat your strike water based on a timer is a game changer in my mind. It allows you to do useful prep the night before with measuring hops, weighing & crushing grain, filling water into kettle(s) and adding brewing salts. Sure, you can theoretically be heating your strike water while you're doing that other stuff, but that prevents you from breaking off that chunk of your brew process and putting it "the day before brew day". And waking up and stirring in grain is where I start the clock on my "5 hour brew day".
2. Sparge is a huge variable. I think some people assume AIO = No Sparge, and therefore round in the time savings of no sparge to the category of "AIO time savings". But of course you can do BIAB with a bag, a kettle, and propane burner. So that's not unique to AIO. And my experiments have shown that when using an AIO, setting the basket up to drain while pouring 1 gallon pitcher at a time of sparge water gets me 5 - 10% improved mash efficiency that I'm not willing to give up. If your baseline is a 1-hour fly sparge, then going to a batch sparge is a time savings- whether you do that on a multi-kettle system or an AIO.
3. Mash time is mash time, whether that's in a cooler, kettle, or AIO. Wort heating if you do multi-step mash is the same, with the exception that a high power propane burner or a 240V electric system will make those steps faster than a 120V electric system. So if you do multi-step mash on a 120V system, you will have a longer brew day, not shorter.
4. You also still have to heat to a boil in every system. And as above, a 240V 5500W element vs 240V 3350W element vs 120V 1600W element vs. high-power propane burner will be different. If you're using a 120v AIO, you will likely see longer times because of this.
5. The reliability, repeatability, and safety aspects of brewing with an electric controller vs. a propane burner frees up your time DURING your brew day. I've brewed during a work day, calling in to meetings at times where I know there's not much for me to manually do. I'll take kids to school. I'll go shower, etc. The list is endless. This is a big time win for electric in any form, not just AIO. It doesn't shorten the start:finish time, but the amount of time spent dedicated to brewing is less.
6. For a lot of people, electric means indoor brewing, and those of us lucky enough means dedicated indoor brewspace. This is also a gamechanger when you don't have to haul everything inside & outside. Again, that's not unique to AIO, but is for electric.
7. AIO have very simple, lightweight "mash tuns" to clean. I always clean my mash tun while the boil (or heat to boil) is going on, so this doesn't shorten the brew day, but it's similar to the above where the stuff you have to do DURING brew day is shorter time so you can spend time doing other stuff.
I'm sure there are others that people can think of. But I would say AIO does not necessarily get you away from a "5-hour brew day".
