January 21, 2019

One Gallon Spontaneous Fermentation Batch #3

Although this is my third attempt to successfully brew a small batch spontaneously fermented beer, it's my first attempt in Colorado. I'm closing in on two years since I brewed the first two attempts so I've had a chance to see how they developed and adjust processes. As I discussed in this update post on those two batches, I never saw much sourness develop. The post was briefly discussed on milk the funk and a few people commented that the hopping rate was really high which certainly could be a reason. I've had some time to think on these beers and how I want to adjust the process and recipe going forward. I don't want to create acid bombs but at the same time some acidity is an important part of the flavor and structure of these beers.

Changes to Batch #3 from batches #1 and #2


This batch will take on two changes from the prior batches to test increasing the acidity of these beers. First, I will reduce the hop rate. I think the commentors on Milk the Funk are at least partially correct that the hopping rate has a negative effect, even using aged hops. I've been using aged American hops which are higher in alpha acids and it's easily possible these hops still have a lot more alpha acid left behind than online calculators state. I will cut the volume in half and see how that affects the beer. My suspicion is that this is not a complete answer for the lack of acidity. I expect that some amount of hop tolerant lactic acid bacteria should have found their way into the beer even if they are late bloomers like pediococcus. 

My other thought here is that the first two spontaneous fermentations cooled too quickly and landed at too cool of a temperature by the time I racked them into fermenters in the house. Each batch was cooled for about eight hours in temperatures running from 35-45F and the beers cooled down to the forties fairly quickly. By comparison, lambic brewers tend to land in the sixties overnight although ambient temperatures are comparable. This difference is easily explained by the difference in volumes. By cooling down to a lower temperature and staying there for several hours I wonder if the bacterial load collected as the wort cools is not getting a necessary opportunity to multiply. If their numbers are low then they might lose the competitive battle for resources as the beer warms back up inside the house. To deal with this issue I will brew this batch during warmer temperatures when the ambient environment is in the upper fifties so the beer will cool to the sixties and cool a little slower. 

Otherwise this batch will keep all the attributes of the prior batches. I'll follow the recipe outlined for batch 1 but reduce the blend of aged American hops down to a mere 0.30 ounces. I will also use pils malt from local maltster Root Shoot rather than the pale malt used in batch #1.

Spontaneous Fermentation Batch #3 Brewday

Brewed 12.14.18.

Turbid mashes are one of those processes in brewing that gets a little easier and quicker with experience. I recall that first turbid mash feeling like I was constantly juggling temperatures and not really sure how to extract runnings from those early infusions. Now I know what to expect and these brew days run smoother but not necessarily faster. It's still several hours of mashing and not just a set it and forget it kind of mash. Nevertheless everything ran smoothly. 

Those milky first runnings
With the mash and sparge finally complete after four hours it's time to get the boil moving. As with the earlier batches of spontaneous beer and the last three years of my solera, I'm using aged hops. I've cut back from using 0.70 oz./gal. to 0.30 oz./gal. for this batch to hopefully develop more acidity than the last two batches. This batch has a combination of 2013 homegrown Cascade and 2011 Belma.

Aged hops waiting to join the boil

At the end of the ninety minute boil the wort makes its way out to my backyard to cool. I decided the best place available on my property for inoculation is the small patio outside my bedroom. It sits beneath two aspen trees near a wooden fence and a pergola so between all this wood there should be plenty of opportunity to pick up a healthy blend of microorganisms.

The wort took exactly three hours to drop from boiling to 59F. In the past two batches I moved the wort between vessels to try to slow cooling and left the wort out for a long period of time. As mentioned above, one of my concerns about the lack of acidity is that I left the wort in cool temperatures for too long which may have stunted early bacterial growth and resulted in insufficient acidity. I tracked the cooling temperature in fifteen minute increments which produced an expected cooling curve.


TimeWort (F)Ambient (F)
7:00pm18340
7:15pm14540
7:30pm12040
7:45pm10940
8:00pm9942
8:15pm9038
8:30pm8238
8:45pm7740
9:00pm7240
9:15pm6739
9:30pm6439
9:45pm6139
10:00pm5939



The cooled wort was then transferred into a 4l carboy while filtering out the hops. I added roughly eight ounces of distilled water to top up the batch to one gallon. I sent it to the fermentation chamber with the temperature set to 69F. I'll keep it at that temperature for a few days to ensure it doesn't get too cool in the basement then cut the heat and let it work at ambient, which is in the low 60s/upper 50s right now.


Fermentation Notes

Day 3: Already showing signs of fermentation. I'm holding the temperature at 72F right now to get things moving.



Day 15: Activity has dropped off and the beer has dropped fairly clear. The aroma is musty, old wet sponge and rotting fruit with an underlying bright navel orange that is nice despite all the weird aromas around it. Although old wet sponge and rotting fruit doesn't sound like a good direction for a beer, this does not strike me as terribly different from other spontaneous experiences.



January 14, 2019

Barrel Aged Americanized Oud Bruin Batch 4 Recipe

Sometimes in homebrewing, especially sour brewing, things don't work out the way you want them to and you have to adapt to what happens rather than what you want to happen. I feel that is where I've landed with this string of barrel aged sour beer. After racking out batch 3 to bottles I wasn't in love with the sample I took from the bottling bucket. I'm not sure if that is a result of filling the barrel after moving it and leaving it full of a sanitizing solution for too long or if it's time to rethink filling this barrel. As a result of my uncertainty I've elected to follow the same process a fourth time to see if I can steer this project back on track. If not, I may consider changing my fermentation blend from my house culture to a lab blend. My house culture is sensitive to oxygen and throws too much acetic acid if given the chance and a two gallon barrel (plus all the racking) is a really good opportunity for oxygen exposure. Alternatively I may change my process to primary ferment in the barrel and then rack out to bottles after two or three months. For now, we'll see what happens with the current process.

Barrel aged oud bruin batch 4 process

This beer follows the same process and recipe for the prior three batches so I'll just link to the original recipe post for the oud bruin and talk about the process. As in the past I brewed the beer and sent it to glass for a month before transferring it to the barrel. I racked out Batch 3 immediately before racking in Batch 4 to the barrel along with priming sugar to help consume any air picked up by racking and hopefully reduce acetic acid production. This beer will age in the barrel for three months before heading to bottles for extended aging.

With each batch of this Americanized oud bruin I've had a small amount of beer that wouldn't fit into the barrel. I've collected this beer for additional aging in smaller vessels and added the excess from each batch into a growing blend of beer. After racking Batch 4 to the barrel I have enough excess beer to fill this 64oz growler. I'm not sure what I'll do with this beer (or if it's even worth drinking or blending) but I'll keep this beer as blending stock.

Freshly filled barrel with Batch 4 and the companion excess beer

For batches 2-4 I've set the brewday ahead of bottling day by about a month to ensure I do all the racking at once. For Batch 5 I'll wait to make that decision until I've tasted a bottle of Batch 3 to help make a decision about whether to stay the course or change the process.

Barrel aged Americanized oud bruin brewday and fermentation notes

Brewed 12.11.18. Did a lousy job taking notes this brewday. Procured 2.3 gallons of 1.071 gravity wort. Pitched house sour culture.

Racked to barrel with 1 oz. table sugar on 1.14.19. Beer smelled and tasted similar to previous batches. Racked excess 0.25 gallons to excess container with 0.25 oz table sugar.