I want to use it for a big cake I have for Sat, planning on crumbcoating tomorrow (Thu), fondant & decorating Fri, and delivery early pm Sat - it'll probably be cut up around 4 or 5 Sat. I simply don't have room for all the cake in my fridge, even if there was nothing else in there lol. Will the SMBC be fine for that long unrefrigerated - 48 hours plus - or should I just use my standby ps buttercream?

I wouldn't go longer than 24 hours for the SMBC. Is it a tiered cake? Are you able to store it at all in the fridge? I personally wouldn't use the SMBC if it has to be out that long.

Sorry! Good Luck!

I agree; although some people swear they can leave their MBC covered cakes out for several days, it is not truly intended to be an unrefrigerated icing. I always refrigerate IMBC cakes except for display and serving (and at that point I don't worry if they sit out for several hours...5...6...it's fine). If you can't store the cake unstacked in the fridge, I too would recommend a counter-stable PS buttercream. If you want a nice bc that is a little less over-the-top sweet, try the Whipped Cream Buttercream here in the recipes section; I used that for my last two cakes that needed to be able to sit out. It's kind of a MBC compromise icing--you actually make a meringue with meringue powder and mix it with a ps/shortening base. It doesn't need to be refrigerated at all.

I never leave it out for more than a couple of hours either. I wonder if it makes a difference if you used powdered egg whites instead of real egg? Maybe you should google that and ask the manufacturer. Let us know what you come up with. I think king arthur flour sells some.

Yes it is tiered, no there is not nearly enough room in my fridge! Thanks all, I really wanted to try the SMBC but will wait for another time

4littlewops, I don't think using powdered or pasteurized matters; I mean if you prepare it the traditional way and heat the ew to a safe temperature anyway, it is essentially the same as using a pasteurized product.

I can go and tell you that, but then I cannot explain why the WCBC recipe I mentioned (which uses meringue powder) specifically states "DO NOT REFRIGERATE" so you can take my theories with a grain of salt LOL. So the truth of the matter is, even though my instinct tells me it won't make a difference...the little voice in my head says "Hmm...maybe it WOULD work..."...???

ceshell, maybe that is something to look into. I think it may play a roll in food safety to use powdered instead of real egg whites. It doesn't say anywhere on the package to keep items refridgerated and it says on the package that its safer than using real egg whites. It may make a difference. I suggest to call the manufacturer to ask just to be sure. I also saw a recipe ( I think of recipezar) about a "mock" IMBC using Fluff instead of any egg white at all. Dying to try this as I am also looking for a more stable and safe room temp. IMBC

Oh dear, this thread kinda worries me! The only reason I started offering SMBC as a filling/decoration was because I read on here it COULD be kept at room temp for a few days (with several people's word for that, not just one lone voice!). My wedding cakes are all fondant covered so cannot be put in the fridge (and like the OP, I wouldn't have room if they could!). All the wedding cakes I have booked for this year are being filled with SMBC, and all will have to spend at least 48-72 hours at room temp before being served due to the complex decorations I have to do on them. I have made SMBC filled (and decorated) cakes before that have been at room temp that long with no problems at all (no-one got sick or died), but now you all have me worried!
My cake schedule is very similar to the op's

Day 1 - bake
Day 2 - fill & cc (SMBC made fresh that day)
Day 3 - fondant & decorate
Day 4 - deliver & serve

Most of my SMBC's have a good slug of alcohol of some kind in them - does that make a difference with preservation?

I am going to the great american cake show this weekend and will ask this question to anyone and everyone who knows what they are doing. I hope to get to the bottom of this and get a straight answer from a pastry chef who makes this on a daily basis. I will keep you posted on what I find out.

I love SMBC and I have used it in cakes, not refrigerated for 48 hours. If you have any questions about SMBC I would turn to Jeanne 'FromScratch'. She has been working with SMBC for a very long time and knows her stuff. There is also a great thread she started called 'Making SMBC', it's very helpful:
http://www.cakecentral.com/cake-decorating-ftopict-594605-.html

would health departments classify it as "hazardous" for liscensed home bakers? i hope not...everything i have read says it is ok out for a day (i don't know about 2-3 days).

In pastry school one chef said 48 hours and one said 2 weeks. Reality is somewhere in the middle.

i think i am going to have trouble getting my health inspector to sign off on it. he did NOT know what it was and then i gave him the recipe (including the heating and holding temp at 160) and told him that most consider it safe to leave out for for a day at least...but he still was thinking it would not be a go and he would have to get back to me (that never makes me feel positive, groan).

he said i should gather documentation about it's safety. aaaargh. now, where do i go to get "documentation"?

not a happy camper tonight