Chances are, if you’re a home brewer, you have a particular style and ingredient you enjoy most. For me, it’s the saison and a sour citrus fruit that I didn’t truly discover until I read Randy Mosher’s Radical Brewing. In his book, Mosher described a stand-in for the Seville Orange, a citrus which is traditionally used by Belgian brewers in Witbier and other spiced ales. Seville, or bitter oranges, are also the primary ingredient in Southern marmalade. As cool and traditional as these oranges are, they can be difficult to find in Southern California and so Mosher suggests the use of whole kumquats as a stand in. The kumquat mimics the sweet, bitter, and sour elements of a bitter orange very closely, but also adds flavors of its own, which I find irresistible. What’s more, despite this hybrid citrus tree’s southeast Asian origin, it’s abundant in Southern California and performs quite well just like its citrus industry brethren.
Since starting my home brewing adventure in 2009, my favorite style to brew, Saison, has been a perfect vehicle for this fruit. I appreciate the style’s flexibility and diversity. Like many other Belgian beer styles, there isn’t one correct variation, but instead a wide sprawling category that envelopes beers of all strengths, colors, and flavors. From dry to sweet, from spiced to virgin, from light to dark, Saison runs the gamut. Most brewers tend to edge towards a golden drink with funky, farmhouse, barnyard aromas, which are often accentuated by the addition of citrus and spices. The saison I brew, originally called Equinox, now Lievre, is a dry, spiced, 7% ABV saison utilizing a custom belgian/french saison yeast blend. When I first brewed this beer I used a combination of grapefruits and Valencia oranges, but since my discovery of the kumquat in 2010, it’s been very hard to use anything else. I think you’ll find that for a citrus saison, lambic, or any beer for that matter, kumquats add a complexity that far surpasses oranges, grapefruit, or combinations of the two.
Prepping Kumquats for Brewing
There are quite a few ways to prepare kumquats for use in beer, but I’m going to outline the method that I find produces the best flavor and results. For this method you’ll need to do little more than harvest, clean, sanitize, bag, and freezel
Kumquats can definitely be found at the store, but the sacrifice to quality and the pocket book may not be worth it. Store bought kumquats are harvested underripe and so many have not had the time to develop their full flavor potential. These kumquats are incredibly expensive especially when factoring in the amount you’ll need for brewing. Store bought kumquats are homogenized and so individual tree character is lost when using them. This character is important when brewing on the home brew level and is a luxury that commercial side can’t fully take advantage of. For example, I harvest many of my kumquats from a tree my friend, Aielo, owns and the fruit from this tree in particular has a spectacular pineapple, coconut, citrus quality. Pina Colada kumquats anyone?
The best method for getting Grade-A kumquats is to find them wild, or rather in your neighbors backyards (thanks Aielo!). Lucky for brewers, kumquats are one of those fruits that people just don’t know how to use and so they tend to rot on the tree, ignored. In addition, these trees, when harvested regularly will fruit multiple times a year, which makes it even easier to stockpile for brew day.
When harvesting kumquats don’t be afraid to be picky. Soft, severely blemished, rotten, and/or shriveled kumquats should be avoided. The fruit should be plucked from the tree without tearing the top. Pulling part of the branch off with a few leaves is better than exposing the inner fruit to the open. Note: This may not be the best method for the tree, but it’ll ensure that your fruit can be cleaned thoroughly.
I find doing a pre-rinse prior to the main cleaning session works really well. I collect all of my kumquats in large rubbermaid bins and then spray them down with water one colander full of fruit at a time. If you do this over your bins you can collect the water and dump into a rain barrel to reduce waste.
After the pre-rinse, use a vegetable wash (I use Trader Joe’s brand Fruit & Vegetable Wash) to remove the dirt. To do this, fill a large mixing bowl half way with water, use a few tablespoons of Vegetable Wash and give the fruit a soak for about a minute. Move the fruit around with your hands lightly scrubbing each kumquat with your fingers. Transport the fruit to a colander and rinse thoroughly while saving the vegetable wash for the next batch of fruit.
Use a final rinse sanitzer like star-san. In another large mixing bowl, fill halfway with water, and add star-san to the proper beer dilution. Using a little over the recommended dosage wont hurt anything, but be sure to wear rubber gloves to reduce the impact on your hands. Soak the kumquats in the sanitizer bath for approximately 60-90 seconds and then transport them to a sanitized colander to drip drain for another 60 seconds.
The fruit can now be moved to gallon sized freezer bags, you can fit approx. 5 pound in each bag, which ends up being a pretty convenient measurement for 5-10 gallons batches of home brew. This method is pretty wasteful unless you reuse the plastic bags, but I have yet to find a better way of storing fruit in an airtight medium. When the bags are full, place them in a stand-up or chest freezer for safe keeping. Freezing is an important step in this method as it works to break the fruit cell walls down. Citrus skin is very tough and is naturally resistant to the elements so weakening it is necessary to get saturation when added to beer.
I typically freeze my kumquats for 1-2 weeks before use. Now that they are frozen, they can be stored this way until you need them. Freezing fruit is common practice in sour beer brewing so don’t be afraid to do it with berries and other fruit as well.
Add to Beer
Whole frozen kumquats can be added to beer at the tail end of the boil or during secondary. Because the fruit has been frozen, it will be brittle, and as soon as the temperature is raised the cells will burst forth with citrus oil. It is for this reason that you’ll want to add these directly to your beer frozen, not thawed. If thawed prior to use you’ll risk losing some truly amazing volatile oils and flavors.
So why don’t you slice, zest, peel, or blend them up prior to use? First off, it’s a pain in the ass. Second, if you blend them up you’ll be blending up the seeds, releasing pectin, and probably some unwanted flavors. Juicing them will add tartness to your finished product, but the contact time with the sweet citrus peel will be absent. De-seeding is an absolute waste of time and you’ll be exposing the inside of the fruit to air for prolonged periods of time. This is also the most sanitary way to add kumquats to beer. Because the fruit peel is strong and intact during the cleaning process, you’ll be able to fully (or close to it) sanitize them provided the inner fruit is not exposed. It’s not aseptic, but if it’s good enough for commercial beer production, it’s good enough for home brew.
I find that long-term exposure to whole frozen kumquats produces the best result. They hold their shape, but fear not, beer has no problem penetrating through a frozen kumquat peel (just like making jungle juice). It makes clean-up easier and you can even eat these beer filled wonders when you’re done with them. If you’re bent on getting every last drop of beer, you can press the kumquats after fermentation, but be warned, they disintegrate fast, which is yet another sign that this method works well.
I love these little citruses and I hope, by using this method, you’ll find a new interest in them as well. If you have any comments or alternate methods, I would love to hear about them. Cheers!