Every fall, the whole family goes up to the foothills of the Appalachian Mountains and we spend a day at an apple orchard. It's great fun, the weather is (usually) beautiful, and you can get an abundance of cheap apples. I walked away with a little better than two bushels of apples for pressing into cider. I've experimented with standard dry ciders, backsweetened ciders, ciders with various yeasts, and wild fermented ciders, but this season, I thought I'd go for something a little more ambitious. This year, I split the batch into a control batch and a keeved batch. What's keeving? It's an old process dating back to at least the 1600's that allowed for the production of a sweet, sparkling cider with no backsweetening. Sound interesting? Let's process some apples and we'll talk about how it works.
Processing the Apples
So, I had about 100 lbs. of apples fresh from the orchard. About 25% were Granny Smith, 25% were Arkansas Black, and the balance we'll call "other". Now what? First thing I do is set up a cleaning station. This will get whatever junk in on the outside of the apple off before it ends up in your cider. My cleaning station involves using a double well sink and filling one side with apple cider vinegar and water in a 1:5 ratio. Most online resources recommend a stronger 1:3 ratio, but I tried to keep it light in hopes of allowing some of the wild yeast to stay on the skins. Add your apples in and let them soak for 10-15 minutes. Switch out the solution in this well every bushel or whenever the water changes color significantly.
The second well of the sink is filled with fresh water. This acts as a rinse for the apples from the first well. You really only need to dunk them for a few seconds, but I end up letting them sit for 10-15 minutes as in the first well. This allows for better pacing and makes apple cleaning and processing move more like a production line. Switch out the water for every batch of apples you put into this well.
Here's the fun part. After the rinse well, I pull out all the apples and put them out on the counter covered with an old towel. This serves two purposes; absorbing a bit of the rinse water and preventing slippage as you chop the apples down to size. Although not pictured, there's a chopping block under the towel to protect the countertop. I use a meat cleaver and it makes short work of any apple in its path. I chop the apples fine enough to fit into my blender. If you think you'll be making a lot of cider, you might want to invest in a nice fruit crusher, but a blender will work. Just keep in mind, this will stress a blender, so you'd either be using a Vitamix or just not care about replacing it if you burn it out.
At the end of blending, you should end up with approximately chunky apple sauce as you can see above. These buckets are each 6.5 gal and they're full to the brim. Here's where I started to diverge the batches. The batch on the right was treated with 2 tsp of pectic enzyme to help break down the pulp a bit more and allow for better extraction. It has the additional benefit of leaving you with a less hazy final product.
The batch on the left was treated with PME (pectin methyl esterase). Without getting too technical, we'll save that for a Simple Brewing Science post, pectic enzyme is actually a blend of different enzymes (that includes PME) designed to completely break down pectic substances. PME, on the other hand, is a single enzyme and only performs a de-esterification of pectin, which is only a partial degradation. This degradation leaves us with demethylated pectic acids.
For now, the gamma lids are screwed down loosely and the buckets are allowed to sit for 24 hours at 33F to allow for oxidation to occur and the respective enzymes to marinate a while. This oxidation allows for additional color and flavor development.
Pressing the Apples
The next day I break the press out and line it with a fine mesh bag. My press is more or less like this one and I like it, but use whatever works for you. I take a nice 1x16 board and prop the press up using the fermentation chamber on one end and a ladder on the other. Fancy, I know.
This is what the apple puree looks like 24 hours after original processing. Quite a change, isn't it? The smell has really opened up at this point too and it's just wonderful. In order to prevent cross contamination, I press the keeved batch first.
I immediately realized there was going to be a bit of an issue, because I was only getting 1.052 from the juice and it needs to be at least 1.055 or better for keeving to work. I took a small portion of juice back to the kitchen and boiled it down to allow it to concentrate a bit more. In order to keep things as even as possible, I did the same for the control batch. It was difficult to keep things exactly the same, as you can tell in the picture below, but the gravities and volumes were close. Before setting them into the fermentation chamber, the control batch got a dose of Wyeast yeast nutrient and a shot of O2. It received a pitched of reconstituted Mangrove Jack's Cider Yeast. The keeving batch got an addition of CaCl2. Why CaCl2? Remember the pectin we were de-esterifying at crush? The calcium in the CaCl2 binds with the pectic acids we made to form calcium pectate. Calcium pectate is an insoluble gel. It binds up yeast, nitrogen matter, and CO2 into a chapeau brun or brown cap. The chapeau brun will slowly rise as it traps more and more of the CO2 from the initial stages of fermentation. Any pectin that didn't become de-esterified will tend to bind with proteins and tannins in the juice and fall to the bottom. What we're left with is very clear and refined juice in the middle that's void of most yeast nutrients. Once this condition occurs, you rack off the juice from the middle and leave the remaining wild yeasts to ferment as well as they can. If all goes well, they'll run out of nutrients before they run out of sugar and we're left with a sweet cider (~1.030).
Fermenting the Cider
The control batch was held at 68F and fermentation was noted to start in earnest within 12 hours. Fermentation was complete in 4 days and final gravity was 0.998. The keeved cider was held at 46F. Nothing really seemed to be happening with it for the first week. I added the control cider to the fermentation chamber at this point to let it cold crash and clear up. I continued to check in on the keeved batch every day for the next 6 weeks. While a few bubbles were noticed indicating some level of fermentation was occurring, it really didn't amount to much, and certainly didn't precipitate the formation of chapeau brun. Then I noticed I had real trouble: at six weeks, I spotted a tiny patch of mold was floating on the top of the fermenter. At that point I called it and carefully racked the cider off from under the mold and above the bottom trub. Later inspection of the trub revealed it was slightly gummy in nature, leading me to think I was close, but no cigar. In an attempt to save the keeved batch, I pitched a reconstituted Mangrove Jack's Cider Yeast into it and allowed it to ferment out in the same manner as the control batch. It fermented down to 1.001. Upon completion of fermentation, I cold crashed both ciders down to 32F. The right side of the picture above shows both ciders immediately prior to cold crashing. I was really fascinated by the color difference! Clearly, I had achieved ... something.
Tasting Notes and Lessons Learned
After a week at 32F, I prepared a priming solution of organic apple juice concentrate and water. The batches were bottled individually and primed to 1.8 volumes of CO2. I chose this level because it's just on the high side of most English session ales and I knew based on the gravity readings that both ciders had ended up as dry English ciders.
After a month of conditioning, I refrigerated a bottle from each batch for 48 hours. I normally like to let cider condition in the bottle a bit longer, but I wanted to go ahead and share the results of this experiment and needed some tasting notes. From the picture above, clarity was obviously excellent. Both ciders are easily the clearest ciders I've ever made. The keeved batch was just a shade lighter than the control batch. That was surprising given their appearance pre-cold crash. Both had very low aroma, but hinted at over ripe apples and earthiness. Carbonation level was right on target for low to moderate. Each cider started off with a clear, crisp acidic bite and tasted of apple rinds and various fruit esters. The end is where these two differ. The control batch tends towards slightly thinner and more astringent finish. The attempted keeve has a fuller mouthfeel and a much more subdued finish. The difference was slight but perceptible. Given a choice, I preferred the keeved batch, but both were really good for a dry cider. For a point of reference, my wife tried the keeved batch and thought it tasted similar to Magner's.
While my attempt to keeve failed, I learned a lot from this experiment. Unfortunately, I think the apples typically grown in this region are dessert apples and not entirely appropriate for keeving since they're too low in pectin. Does that mean a keeve will never work? I think I've worked out how to overcome this for my next attempt. First change that will need to be made is holding off on adding the PME at pressing. The juice should be pressed, then immediately hit with an addition of potassium metabisulphite. This should allow the keeve to start with a clean slate. 24 hours later, liquid pectin should be added along with PME. This would ensure enough pectin is present to produce an appropriate amount of pectic acid. After another 24 hours, the CaCl2 and yeast should be added. The yeast should be underpitched, but I'm still a bit on the fence on exactly what yeast to use. I'm currently teetering between using something along the lines of WLP720 (White Labs Sweet Mead) or other less attenuative strain and hope the tendency for it to leave residual sweetness would make it a good candidate. The other idea I had was to use something a bit more like a wild strain of yeast, perhaps a saison or even a Brett, and hope that the lower temperatures will help keep it in check long enough for the chapeau brun to do its thing and starve out the remaining yeast before it can fully ferment the cider.
One great thing I discovered was boiling down a portion of the cider to concentrate it. I love the color and flavor development that it provided. A tasting of the concentrate had shown it to intensify all the best parts of the apple. It also struck me as a great time to add some other flavors for balance. Since most dessert apples lack tannin, my thought was adding some English breakfast or Earl Grey tea immediately after the cider is taken off boil and allowing that to steep a while during cool down. The Earl Grey might be a bit better as it could add to the complexity of the acid profile as well as add some tannin.
At the end of the day, was this even really a failure? I still have a lot of good cider to drink, even if it isn't the cider I envisioned from the beginning. I have a ton of ideas for next fall's apple crop. There's also been a couple of new additions to my Amazon wish list, so I'll have more material to study while I wait for that apple crop to arrive. I can drink to all that.