Keith Ciani on Staggered Fermentation

Keith, on behalf of all those brewers out there who are always on the look out for something new, creative, maybe even crazy to brew - thank you for taking the time to answer our questions. 

You know, I've been brewing for five years and when I saw the piece by ChopandBrew.com about how you accomplished a staggered fermentation to make your 14% "Anglozilla," this thought popped into my brain, "that is flipping awesome!"

So, being that I'm a fan of awesome, and I know a lot of folks out there are also huge fans of awesome, I thought maybe you'd be down to chat on this avant-garde and little talked about technique. And you were, which is also awesome, so let's dive in.

First of all, what would you define as a Staggered Fermentation, disregarding (bottle reconditioning)?
I conceptualize staggered fermentation as multiple yeast additions --- in a sense, feeding the beer over time. Rather than feeding with honey and/or other sugars post initial yeast pitch (as is popular in many styles) – this requires yeast following yeast – sometimes over a number of days.

What beer, brewer, article or spark of divine inspiration drove you to plan and execute your first staggered fermentation?
This idea (at least for this particular beer) primarily came from Todd and Linda Haug of Surly Brewing, and their 6th anniversary beer, Syx. I was living in Downtown Denver and heard Surly (and the Haugs) would be at the Great American Beer Fest. I had previously chatted with them at Avery Brewing’s Strong Ale Fest a few months prior and so I invited them to my condo. I was having a party in which I was tapping a cask/pin and serving some pork shoulder. They were unable to make the party, but someone brought a bottle of Syx. 

Syx is a 14.5% abv American Strong ale (with wood character). The beer blew me away --- it was not overly sweet and was quite unique (I recall an orange character). Anyway, I ran into Todd and Linda on the floor at GABF and asked about the beer. Todd mentioned feeding the beer with yeast over time (and perhaps even more fermentables…but I can’t recall for sure). I believe they used white labs super high gravity, but again, I can’t be sure. That was really the first time I had heard of this, as least intentionally (e.g., new brewers adding more yeast due to pitching insufficient cell counts). 

Secondly, Don Osborn provided some peripheral impetus for staggering the fermentation. I mentioned the recipe to him and he brought up the issue of alcohol tolerance of English yeast. This is when I began thinking about using different yeast strains with varying levels of alcohol tolerance. To a lesser extent this was also inspired by brewing a number of sour beers and beers with Brettanomyces, in which staggered additions of wild yeast and other bugs is common. 

When you are planning a beer, are there certain characteristics you decide your looking for where you say, hmmm, ya know Keith, this is a good spot to do a Staggered Fermentation. What are some of these characteristics and how do you go about achieving them?
While this is the only beer I’ve done this with --- anyone brewing something above 12% - and/or with a potential abv in the range of 12-16% should seriously consider this method. When doing multiple pitches, what is your thought process behind pitching rates? I only have the one example to go from – that said, there are yeast counts and flavor profiles to consider when staggering a fermentation. As I discussed, I brewed an English (very) Strong – so I wanted/needed a bit of English yeast character. However, the strain of English yeast I used would not be able to ferment that beer to an acceptable gravity. I started the fermentation off with WLP 005 (British ale) to get that initial yeast character, and then followed it up with numerous starters of Cali Ale 001. The thinking behind adding starters of cali ale after fermentation had already started was primarily to pick up attenuation where the British ale would have likely stalled out – and secondly, to not interfere with the British ale yeast character. My yeast additions are available in the recipe provided.

As we know, the majority of the flavor compounds (esters, phenolics, fusels) are created in the first 24-36 hours of primary fermentation. Any thoughts on how a staggered fermentation is affected by this aspect of the big picture? 
Regarding the flavor profile, the beer I did was conceptualized as an English Strong, but it was also very much a Barleywine type ale. Thus, I wanted English yeast characteristics to be apparent. I started the fermentation off with multiple starters of While Labs 005 (British Ale). Knowing that yeast (005) does not have a high alcohol tolerance, I followed it up with multiple pitches of 001 Cali Ale. As we all know, that yeast has a much higher alcohol tolerance, and would not mask/overpower the profile from the 005. In order to avoid unwanted flavor compounds, that could be imparted during fermentation, I made sure to oxygenate the wort not only prior to the initial yeast pitch, but also on the 2nd and 3rd days after fermentation began.

What about oxygen? Generally speaking, what can you tell us about its role and use in this process?
This is the counter-intuitive aspect of staggered fermentation involving a big beer --- you WANT to re-oxygenate after fermentation has begun. Introducing oxygen after fermentation has already kicked in is usually ill-advised for a number of reasons; however, this process can be quite important for a beer of formidable abv (e.g., 12-16% or so). The yeast are already stressed given the environment, and they need new/more oxygen to keep working. This is also true of the new yeast that is staggered/introduced in stages. I cannot speak to specific oxygen schedules – or even the exact science behind it – but my process is listed in my recipe (below).

Can you share with us any general warnings, gotchas, or "Oh my lord, and for heaven sake dont do that!" pointers you may have?
Regarding staggered fermentation --- be ready to tweak your plan. You may or may not hit the original gravity needed for multiple yeast additions. When I brewed this particular beer, my system was less than efficient. I made up for that with a three hour boil. I ended up with a much higher OG than anticipated and had to immediately build up more yeast to follow the initial pitch. Also, be aware of the varying levels of alcohol tolerance of the yeast strains you choose. 

And conversely, can you share with us what you have found to give you the greatest success in this process?
Beyond the importance of having a lot of experience with the fundamentals of homebrewing (e.g., yeast count, ferm temps, etc), being near the beer during the first week is very important. I am a stay-at-home dad, and also work a bit from home. This allows me constant access to my fermenting beers. This might be tough for someone that is away from home during those first 1-3 days. 

Do you have any brews involving Staggered Fermentation on the brew plan in the near future? Maybe…that beer was a lot of work and extremely expensive – and many things can go wrong during the process. However, my wife just mentioned she’d like something similar this year. I also just upgraded to a 10 gallon brew system – which would make brewing five gallons of this (or a similar) beer much easier. Another pro is that they tend to last a long time. 

Can you share with us the recipe you are most proud of where im you used the process?

English Strong (very strong) - aka Skywalker OG - aka Anglozilla 

5 gallon batch (more like 3.75 gallons after boil) 

25 lbs maris otter
1 lb english chocolate malt
1 lb of EKG leaf hops (5.6%aa)
wlp 005 and wlp 001 

*I had a 54 qt mash tun cooler - so there was room

90 min mash 150 - 148 degrees 3 hour boil (can't find what my preboil vol was, but it was likely around 7 gallons...was down to 3.75 gal after 3 hr boil) 

*preboil gravity was 1.090....post boil was 1.148!

Hop schedule (ibu estimation 71):
4oz at 120 min
4oz at 45 min
4oz at 10 min
4oz at 1 min 
*each addition in a muslin bag or two, so they can be removed...whole leaf 

Yeast: two big starters of wlp005 - pitched after aeration (ferm started in 1 hr) - however, 005 does not have the alcohol tolerance to ferm a 1.148 beer down to an acceptable FG --- made two big starters of 001 to add later 

Aeration and yeast schedule: 
brewday: aerate and pitch shit-tons of 005 
Day 2: re-aerated
Day 3: morning - brief re-aerate and pitch starter of 001
Day 4: evening - pitched other starter of 001 ferm temp was around 67-72 entire way (let free rise to 72 towards end to help attenuation) 

*gravity sample after 2 weeks was at 1.038 (approx 74% attenuation, ~14% abv)

*racked after 25 days (still at 1.038)

*kegged 33 days after brewday (still at 1.038) 

I heard you just moved from condo brewing to garage brewing. That's a home run! What is the greatest asset you now have in your brew house, you didnt have in the big bad beer loving city of Denver? 
A F*CKING PUMP!!! 

Well Amen to that! Keith, once again thanks so much for sharing what you've learned. I hope this gives people the inspiration to try something truly unique and the tools to make those beers not only good, but awesome!