Thursday, April 18, 2013

Local Lambic - Part 1: The "Bugs"

After reading a blog post by The Mad Fermentationist that Scott (SNB Brewing) sent to me 2 years ago, I decided to brew a beer and ferment it using a local wild starter, thus my Local Lambic project was born.

In order to capture my local wild yeast & bacteria I boiled up some wheat DME with Styrian Golding whole hops - O.G. 1.027 with an IBU of 23. The half gallon of cooled wort was divided into 3 shallow vessels and covered with cheese cloth. A sturdy rubber band was affixed to hold the cheesecloth in place and keep any big bugs and leaves out while the starters were set out overnight to be inoculated.

One was put in the washing machine near my brewing are in our garage.
Both side doors were left open so it would be exposed to a draft breeze all night long.

One was put in the middle of our vegetable garden.

One was put on the other side of our back yard near several citrus trees.

My plan was to allow each starter to ferment individually to see what developed from each inoculation location. Any rank foul starters would be dumped. If any of the little starters goes bad I'll be able to smell and taste it. Only the good ones make it to the next round where I would increase the cell count with a larger starter Hopefully, I'd work up enough yeast and bacteria to ferment a 5-gallon batch of homebrew.

With this approach I wasn’t forced to just roll the dice and hope spontaneous fermentation happened with the right mix of yeast and bacteria after investing the time and money to brew a full batch with the hope that it would ferment into something flavourful.

The wort “Petri” dishes made it through the night OK, but one earwig made its way into the wort left in the garden. Who knows what type of “bugs” were on that bug! In the future, I recommend using a double layer of cheese cloth to keep out the med. size bugs too.

Here's the collection of 3 canning jars with inoculated starters that were nice and safe after a night of running wild in the back yard...

In just 2 days, one of the starters was already starting to show signs of fermentation! Go figure, the one that had the earwig fall into and it’s the one that got going first!

By the 3rd day, all 3 of the inoculated “Lambic sisters” were fermenting away nicely. They all still smelled like fresh wort at that point. No other distinct aromas, but more importantly, there were no noticeable off-aromas!!

At that point it was full steam ahead for the project - Ramming Speed!!

What was collected from my back yard was definitely some type yeast, but the wort could also contain bacteria like lacto., pedio., etc., and probably some brett. I kept my fingers crossed that the earwig didn’t add any e.coli from the planter soil or any other nasty bugs. Luckily, “bad bugs” make beer smell and taste bad and the low pH of fermenting wort kills off e. coli. The blog posting from The Mad Fermentationist that Scott mentioned to me talks about this stuff in detail and is a real eye opener on how to logically and safely collect ambient yeast and bacteria for use with homebrew.

I also created sour starter that used raw grain to create some soured wort that went into the wort once it cooled below 110 degrees. This was done to create add some complexity to the sourness in the beer and help drive the post-boil pH down. It also ensured I had desirable bacteria in the mix.

My plan was to conduct primary fermentation in glass and then age in stainless steel. Both can be easily sanitized afterwards. I couldn't match the oxygen that permeates through oak, but I planned on opening up the corny keg and allow fresh oxygen in to help control the brett., pedio., lacto. & acetobacter. Other than that it's a bit of a crap shoot - as they say "Relax, have a homebrew”

I tried to control what I could, and prayed the rest went down the right road. I’d never done this before, so it’s as much a learning experience as a chance to manage a fermentation that is much more complex than any other I've attempted.

After 3 weeks, all 3 starters had a yeast cake at the bottom, and 2 out of 3 have signs of brett. too. I think the secondary oxygenating I did increased the amount of brett present - nice white film on top of the starter.

Because all 3 starters came out so well, I combined them to inoculate a full gallon and a half starter for the Local Lambic. I oxygenate the new starter by shaking it quite a bit in order to grow the max. amount of yeast cells. They'll have to do the bulk of the fermenting of the wort after all. The rest of the bugs in the mix would do their thing afterwards with the “scraps” after primary fermentation was finished.

The yeast, etc. grew nicely in the second starters. Whenever I shook up the bottles, the amount of latent carbonation is amazing!

Houston, I think we are ready to start countdown for liftoff!

While the aroma of the starters was becoming less "worty" I had not tasted it yet. The real flavor of a Lambic doesn't come from the yeast anyway. It smelled fairly clean with a faint lemon aroma.

I'll planned on giving it a taste a week later to see where it was at, but I needed it to ferment for a while to make sure there's no chance of e. coli before tasting it. Luckily, the drop in pH caused by yeast fermentation kills off a lot of really bad bugs. The yeast cake at the bottom is a bit dark, but it's nearly 1/4" thick now!

I wanted to ensure I had all the hallmark bacteria found in lambic fermentation, so I supplemented the wild yeast & brett. I’d captured with bacteria from the grain used in the mash. I made the soured wort as outlined in a BYO article to add to the cooling wort. I boiled 42g. of wheat DME in a pint of water for 20 min. When it had cooled to 110 degrees, I added 1/3 cup of slightly crushed Belgian Pilsner malt. The whole mass came to 100 degrees. It would need to sit insulated with a heating pad under it to keep it between 100 and 120 for the next 3 days. Grain husks have bacteria on it that will attack and eat the sugars in the starter. I hoped yield a good bit of lactobacillus & pediococcus which I planned to pitch into the cool-ship once the wort was about 100 to 110 degrees Fahrenheit. As the wort cools slowly overnight, it will give the bacteria time to grow before the yeast is pitch.

Here are some photos of how I created the Sour Wort Starter

Close up of crushed malt

Starter and crushed grain.

Grain in the starter wort

Starter was snug as a bug. I pushed a food thermometer right through a small hole I make in the lid in order to constantly monitor the temperature accurately.

Starter resting nicely at 100 degrees

4 days since the soured starter was “brewed” and it has really taken off!

The Local Lambic starters didn't show signs of either of these bacteria, but they gave me signs of Yeast and brett. activity. The two starters together should make for a good lambic with some complexity to the sourness.

In Part 2 (due in Mid May) I’ll discuss the brew day, fermentation and final flavor profile of my Local Lambic. How to make your own cool-ship and lessons learned will be included too!

1 comment:

  1. Best of luck! I was surprised that my first try at a spontaneous batch turned out not only drinkable, but enjoyable! Hopefully you had the same good fortune.