You know how you can never get that last bit of LME out of the container in time for it to be part of the wort. Well, I started saving those leftover bits a year or so ago and now I have about 12 lbs of mixed LME along with some random hops from prior brews taking up space in my fridge. I even have some leftover crushed grain I can use as steeping grains. I was considering just mixing up a frankenbeer and use one of my washed yeasts, but I thought if I’m going to make something utterly random, why not go the whole 9 yards and try an ambient fermentation.
I have ordered a 6" deep full sized hotel steam table tray which will comfortably hold 6 gallons of liquid. My plan is to do a 1 hour boil using 6 lbs of LME (which should yield a guesstimated gravity of around 1.040) and 15 IBU worth of my oldest hops. Then transfer to the steam table tray, cover the whole thing with cheesecloth, and set it in my basement brewery with a fan stuck in the window near the ceiling for airflow.
I have questions:
How long should I expect to wait for fermentation to start?
Assuming it starts, how long should I let fermentation go on before transferring to a carboy and applying an airlock?
Is cheesecloth the right choice here? I want to keep the actual insects out but leave enough of an opening to allow the microscopic bugs to get in.
Is the fan really necessary?
If I were to use the full 12 lbs of LME (along with more hops), what would happen? Would there be early on microbes that would die off as the alcohol level rose who would be replaced by other critters that are able to tolerate the alcohol and finish the fermentation or would I just end up with a tray full of sugar water?
In Belgian ambient fermentations, you get aerobic bacteria that like warmth like enteric bacteria. As the oxygen is consumed and the temperature goes down anaerobic microbes take over including wild yeasts and lactic acid bacteria (LAB). As the alcohol increases, you winnow out the various anaerobes; the LAB may stop especially as you approach 8% and some yeasts may continue. Pedio could take over…
I assume that you’ll transfer to a closed fermenter at some point.
Never done an actual ambient fermentation. I like paint filter bags. They have approximately the same mesh as cheesecloth.
in my experience with somewhat similar stuff you have a very good chance of just growing moldy wort. I suggest you save the old LME for starters or something.
We have a highly regarded spontaneous fermentationj brewery around here named De Garde. Last time I talked to the brewer they were were hoping to get their dump rate under 30%.
One thing to think of is that the thermal mass of a commercial brewery’s batch size is much larger than a 6 gallon batch. This means that your batch will cool a lot faster and spend less time in the temp zone that is best suited to lactic microbes. One way to balance that out might be to throw in a handful of pilsner malt at the start to innoculate with some wild lactic acid bacteria.
Another way to innoculate with wild microbes is to add fresh, local fruit that hasn’t been cleaned. The skins will have plenty of wild yeast and other microbes. Blueberries, gooseberries, currants, and cherries are options this time of year, nectarines, plums, apples, and cranberries are options as we get closer to the fall.
Whatever you choose, be aware there is a high likelihood that this could be a dumper batch. But have fun with it, and keep us posted on it’s progress!
a seldom talked about point in regards to these spontaneous ferments is that professionals often rack them into used wine barrels which are loaded with yeast. Alot of the “spontaneoud fermentation” happening is from the wine yeast that is already in the barrel
In addition to being curious if I can make a drinkable beer, the “fertility” of the air what I’m trying to gauge. We’ve had great luck with sourdough bread from a starter I made using dried spent grain run through a food processor to make “flour”. But that’s upstairs in the kitchen away from all of the fermenting fun. Part of the reason for doing this is that I am curious what the microflora in my basement are like after 7 years of brewing everything from American Pale Ales to pseudo lambics but focused mainly on Belgian Trappist and farmhouse ales. If it turns out my borderline OCD cleaning regimen has thwarted the critters from establishing themselves, I have a lemon tree and a raspberry plant in my yard so there is a possibility of completely unprocessed, unwashed produce to put in the room with the wort for the next batch.
In re the question about racking into a closed fermenter: yes, that’s the plan. I am anticipating a week in the “koelschip” pan and then into a 5 gallon secondary. For this first batch I will rely on a big ass “splashless” funnel, but before I do another I am going to go to the home-brew store and pick up a bottling spigot to mount in the bottom of the tray to reduce the probability of sticky goo all over the floor.
Moldy wort would not be a problem, it would be a learning experience! I have no illusions that this first batch will produce anything drinkable. If it does, that would be awesome. If not, I have an experiment under my belt, some datapoints I can apply to future experiments (for instance: I imagine I should be waiting until winter to do this but I’m actually curious to see what happens), I’ve freed up some valuable refrigerator space which will make the wife happy which means she will be less annoyed by my excessive brewing habit.
If it goes well, I will do an actual all grain lambic recipe next and go for an actual ambient fermentation lambic. If it is a bust, I will wait until the weather cools down a bit and try again. Either way, I’ll keep adding info here as requested.
a week in a shallow pan, and I can virtually guarantee you will get mold. that is way too long. Have you looked up bioprospecting? That is a much better way of getting wild things.
This is the advantage of doing this while I’m stuck at home and not going to work every day, I can check it three or four times per day. I’ll rack off if things start going sideways.
Bioprospecting is something I’ve considered as well but since I’m trying to stave off boredom and I have the raw materials sitting in the fridge, I’m willing to roll the dice.
Just curious: Is this something you have experience doing? If so, I’d be interested in knowing what has actually worked.
Thanks. I am basing my “process” on some notes I took watching an old interview with Patrick Rue when I first started brewing about 7 years ago. I figured he is as good a role model as anyone for this type of thing.
When I first started this, I suggested that I was going to do that and my wife said “That would be a hard no.”
My plan is to build a wooden “tunnel” that will hold the fermenter and then inoculate that. If I get really crazy, I might look around to see if anyone has published the dimensions of the room where Cantillon has their koelschip and the dimensions of the koelschip and then build something to scale.
Amazing the stupid crap I’m coming up with to stave off the boredom of being stuck at home …