I've been enjoying this thread and have even learned a few new things, which I wasn't necessarily expecting having switched to a simple propane BIAB setup (no recirc) about 5 years ago after starting with Denny's batch sparge method. Over the past 1-2 years, I've been looking at upgrading to some sort of electric eBIAB system, with the hopes of removing some of the more annoying parts of my brew day - having to constantly check the temp of the strike water to get it where I want, mash temp variation that depends on the outside temp that day, the pain of doing any sort of step mash without recirc, and constantly going in and out of the house to split the time between brewing and family duties.
Regarding the Spike Solo, is this high amount of grain that makes it into the boil something you've personally observed, based on the early user reports, or something that Spike themselves has mentioned? I'd expect there to be a little more material that makes it through since the slots in the bottom of the grain vessel are probably a bit wider than what a bag would have, but more than a few ounces sounds a bit excessive to me, not to mention a few pounds. Then again, I haven't ever measured how much I'm getting with my current method. I expect this would be a similar issue on some of the other all-in-one systems with a similar design (Unibrau is another I've looked at)? Or is there another aspect of the design of the Spike that makes it more susceptible to this?
There are 2 other drawbacks with some of the all-in-one systems that I've been seeing while doing my research, that have kept me on the fence with this for so long. The first is that the systems with solid grain pipes/vessels all tend to limit the max grain bill relative to a simple bag system of the same size, and some are worse than others. The Spike seems to be the worst offender here with the tapered basket design, as they list a max grain bill of 12lbs on the 10 gal system. I'm not sure I'd want to jump up to the 15 gallon, since that seems a bit much for the ~4 gallon batches I'm usually doing (I'm a corny keg fermenter guy), but I can't imagine I'd be able to reach an OG much above 7% on that system in a 4 gallon batch. Many of the others I've been looking into at seem to do better in this regard (Unibrau, Clawhammer, Brewtools, Grainfather), but it does seem to be a drawback (especially at the ~5 gallon batch size) vs. the simple bag with a false bottom method. Of the ones I've looked at, the brewtools B40 seems to probably do the best at getting around this issue as well as the grain making it into the boil, but dang, that thing is pricey and doesn't look to be easily repaired with standard parts should a pump, heating element, or controller fail.
The other "issue" that has been a concern to me with some of the AIO systems is how they spray hot wort all around almost as if they're purposefully trying to aerate the wort (Grainfather, Brewtools, BrewBoss, Braumeister). I get that they're trying to avoid the pump from drying out the heating element and I'm not following a LoDO hot-side process, but it is something that I'd like to minimize as much as possible. I didn't realize there was actually a low oxygen kit available for the Braumeister before
@Brooothru mentioned it here, but that's something I'm definitely going to have to look into that might bring that system back into consideration for me.
Obviously, these "drawbacks" aren't drawbacks of BIAB brewing itself, but I could see how someone comparing electric 3V systems or electric all-in-ones could make some arguments against a lot of the systems that are currently out there. That being said, if none of the fancy all in ones seem like they'd be a good fit for me, I'd probably end up a simple bag and false bottom before adding 2 more vessels to deal with during my brew day.