October 20, 2010

Working with Agave


I’m about to buckle down for finals this semester, so I’ll shortly lose the time to brew or ponder about brewing (let along write about it!) I have just wrapped up some fun experiments with agave syrup and I wanted to add some first hand and slightly more definitive information than what I found online. Let’s say I wanted to see what it would look like freeze distilling (aka freeze concentrating aka jacking) fermented agave wine to see how close I could get to making something tequila-like. (You can get reasonably close to something tasty but not really the same. More like an agave brandy, but more on that later.) When I started this experiment a month ago, I couldn’t find much clear information on what would happen if you tried to ferment any of the agave products available in grocery stores nor was I familiar with making mead, so I had a steep learning curve ahead of me. I learned a lot from this experiment and I did make some cool stuff, which I’ll talk about. Since I want to preserve and share what I learned, I’ll write more expansively than just what I did.
Available Agave Products
There are two main agave products available in the grocery stores in my area (Texas) and I understand these products are generally available across the US. One is agave syrup, which is often found in the sweetner/sugar aisle of grocery stores. The other is agave nectar, which is typically found with honey. Agave is a plant native to Mexico. It is most commonly used for making mezcal and tequila (I realize tequila is a kind of mescal), by cutting up the heart of the root system, boiling it, and then fermenting the must. It is then distilled to make the particular spirit. Mezcal is any form of distilled liquor made from agave. If it is made primarily from blue agave, it can be called tequila in Mexico. In the interest of expanding the Mexican economy, some smart feller or gal figured out you could refine the sugars in agave to make various sweeting products, such as the two mentioned. As the impurities and flavor is refined away, it becomes agave nectar, which has a honey-like flavor and consistency. As it is further refined, it becomes agave syrup, which is clear and flavorless. Agave sugar is primarily fructose, so it is similar to high fructose corn syrup (HFCS). Some people say agave syrup is worse than HFCS because it has a higher fructose concentration; others believe it is a more organic and healthier sweetner option. I don’t take a stand on this position because for us, sugar is simply a fermentable fuel to create alcohol.
Agave syrup, as stated, is clear and flavorless. In large quantities, it probably has some slight honey or agave (think tequila) flavor, particularly when fermented. It is more apt to be used as an adjunct to raise the alcohol content of a beverage. I doubt if it were fermented alone it would have any flavor or produce anything enjoyable. Since it is mostly fructose and water, it must ferment very dry and probably produces cider-like flavors, similar to table sugar. It could be used in recipes in the place of table sugar, corn sugar, corn syrup or golden syrup (which is really just corn syrup). It would require finding the brix or OG of agave syrup, which is probably available online or available through an agave syrup distributor. However, I won’t spend any further time on this product because I believe if you are looking for a high-sugar adjunct corn syrup is just as good of an option and it is much cheaper.
Agave nectar, on the other hand, has much more varied uses. It is similar to honey in many ways. It has the same thick viscosity, a similar taste, and close to the same sugar breakdown as honey. This is why it is a common substitute for honey in many vegan or vegetarian recipes. In (much) higher concentration it does begin to develop a more agave/tequila flavor. It does have a much higher ratio of fructose to sucrose and maltose sugars, which is harder for yeasts to work through. Keep in mind that since agave nectar, like honey, is almost completely sugar and it can ferment very dry (although in my experience slightly less dry than honey). Research indicates it has the same OG as honey (about 1.034). Most agave nectar in grocery stores will be well processed, so it will have much more of a honey flavor. You may be able to find “raw” or “natural” agave nectar that has more impurities in it and more of a distinct agave flavor. Agave nectar, as I will explain in greater detail below, can be used as an adjunct, in place of honey in beer recipes, to create braggots, in meads, or even fermented by itself as an agave wine (or mead, depending on which you want to call it.)
The most importance difference in agave nectar and honey is the flavor issue. Honey tastes like honey no matter how much you use. Once you use enough honey in a beer to reach the flavor threshold it tastes like honey. It will taste like honey no matter how much you add. It just becomes a question of how much you will be able to taste the other stuff in the beer against a large quantity of honey.
Agave nectar is a strange beast to work with. Agave nectar will taste a lot like honey in small amounts. It does take a good amount to reach the point where it starts to create a tequila-like flavor. If you let it ferment dry it will taste a little like tequila and a lot like fermented table sugar. It doesn’t have the same complex flavor of fermented honey as a result of the refining process that removes the flavor components that otherwise would be left after fermentation. You could stop the fermentation process before it dries out – and using ale yeast it probably won’t ferment out completely – but then you will get sweetness without the agave/tequila flavor. For more discussion about the transition of flavor, look to the tequila-attempt at the end.
Using Agave in Beer
I’ll discuss using agave as an adjunct and like honey/replacing honey in beer and save the braggot discussion with mead. Although you can use agave nectar in beer as an adjunct, it will leave a distinct flavor in beer, much like honey will. I would strongly urge using a more neutral adjunct if the goal is simply to bolster alcohol content. The real value of agave nectar in beer is to consider it as a flavor component. Agave is getting some commercial play in beers. I’ve seen an agave wheat and I believe there is an agave brown(?) and several others on the market. Agave is perfectly fine to use in place of honey in other recipes. At low amounts it will produce a flavor very similar to honey. As it begins to increase as a component of beer, it will undoubtedly begin to take on a more agave/tequila flavor.
It can be added during the boil, but it is not absolutely necessary since it should be pasteurized. It should probably be added at the very end of the boil just to make sure it dissolves easily. It could also be added in a secondary fermentation alone or with other items. It could be used for priming sugar as well. Keep in mind that because of the high fructose content, the more you add and the later in fermentation you add it, the more it will be necessary to add yeast nutrient and possibly yeast energizer to make sure the yeast can ferment the agave nectar.
Because of the quirky nature of agave nectar, it may take some experimentation to figure out the balance between dryness and agave flavor and alcohol content. Agave nectar can dry out too much and give the beer a cider feel or it can leave more sweetness than desired. Because ale yeasts will not want to ferment so much fructose, it could take a long time for it to completely dry out. It can leave a honey flavor or an agave flavor. One thing is clear: the more you use the more alcohol content you beer will have, since it is composed almost entirely of fermentable sugars. If I were trying to make a beer with agave flavor, I would probably start out replicating a honey beer recipe (such as a honey brown) and adjust up or down to figure out the sweet spot. You may also want to consider making a braggot with agave nectar substituted in (keep reading below).
Using Agave in Mead and Braggot
Before this set of experiments, I had zero experience making mead. Not realizing at the time that yeast didn’t like fermenting honey, or agave nectar for that matter, because of the lack of nutrients and the high fructose content, I was really disappointed when my ale yeast failed to ferment a blend of table sugar, water and agave nectar. I thought it would ferment just like making apple juice into cider. Yeast nutrient alone was not enough. I did discover that the combination of yeast energizer and yeast nutrient helped get a sachet of champagne yeast in a gallon fermenting. For that reason, agave nectar should definitely be thought of as honey for the purposes of fermentation. In fact, since it is less nutrient-rich than honey, it may be worthwhile to add a little more energizer and nutrient than a normal mead.
Agave nectar does make a great contribution to mead, but it should not be used alone to make mead. Although it tastes like honey before fermentation, the same problem beer brewers will face in the sweetness/dryness to honey/agave flavor balance will also take place in mead. If it is fermented alone, it will dry out to a point of tasting sort of cider-y. It will not taste like mead in any respect.
However, it can be substituted in a mead to either make a dry or sweet mead. For some reason the combination of fermented honey and fermented agave nectar really makes the agave/tequila flavor stand out. I find that a pound per gallon will dry out and leave behind a tequila-like flavor and dryness in a mead. A 2.5 lb honey and 1 lb agave nectar per gallon mix should yield an alcohol-potent mead with a nice tequila flavor up front. I don’t have too much experience with tasting meads but this is by far my favorite. If one wanted to make a braggot I believe a similar combination of honey and agave nectar, in place of using just honey, would help bring out the agave/tequila flavor without falling into the trap of trying to balance the nectar by itself.
Agave Wine
Yeah, we’re getting closer to what popped into your head when you thought of fermenting agave nectar (ok, it’s what popped into mine). If you ferment agave nectar alone, you will produce some sort of agave wine. As I mentioned before, it requires a lot of nutrient and energizer because it is so nutrient-deficient on its own. If you do make an agave wine, it is going to dry out considerably and have a sharp cider flavor unless you prefer it sweet and stop fermentation. Those of you who are winemakers may have better experience and better luck fermenting something you enjoy.
Pretending to Make Tequila
Now we’ve arrived at what you were hoping for! Unfortunately, the answer is no, you cannot make tequila just by fermenting agave nectar. Tequila is fermented from an unrefined source of agave, so it has a lot of flavor, even after distillation. Those of you with stills may be able to get in the neighborhood of tequila but unless you can get a really unrefined nectar it’s not going to pack a lot of flavor.
Let’s say you don’t have a still, but you point out that recently the TTB admitted it doesn’t consider freeze distillation to be “distillation” in the sense that the federal excise tax laws use it. While there are separate legal considerations from following an agency pronouncement unsupported by anything textual, let’s assume that to be the case. (I know there are some non-US readers of this blog. I am unsure of the state of the law on this subject in other countries. I believe many countries specifically outlaw the practice for reasons I am about to mention.) Freeze distillation will not make tequila; it is an imperfect and risky process.
While I don’t intend for this to be a treatise on freeze distillation, it’s necessary to talk a little about it. Freeze distillation is the process of freezing a volume of alcoholic beverage slowly so that the water will freeze, but the ethanol with a lower freezing point will not, so you can drain out the liquid/alcohol and leave behind the ice/water, thus raising the alcohol content of the beverage. While this is easily done in a standard kitchen freezer, it is an imperfect process.
Part of the imperfection is a reflection of fermentation and represents a health risk. When fermentation occurs, yeast also discharge fusel oils, methanol and other higher alcohols which are either scientifically confirmed or suspected to cause or worsen hangovers in lower amounts to causing nausea, deafness, coma and death in higher amounts. Freeze distillation, by removing the water content, concentrates these byproducts so that the more freeze distilled beverage you drink, the more concentrated amounts of this stuff gets into your body. Now you can say that one gallon of a beverage not distilled and the remaining liquid from freeze distillation contains the same amount of these byproducts, and I would agree. However, it is like taking shots of whiskey and an equivalent amount of beer with the same amount of alcohol. Which will get you drunk faster? The whiskey will, because the concentrated alcohol will enter your bloodstream quicker and you are drinking less water to help flush it out. Similarly, the fermentation byproducts are more concentrated so they can affect you more easily. That effect is compounded if you are drinking a lot of it.
Now people who brew to distill often use “turbo yeast” and don’t worry about temperature control during fermentation, which increases these undesired byproducts. It doesn’t matter if they are there because a proper distillation will get rid of them. However, in freeze distillation, they don’t go away. For us beer and wine brewers, we are generally more concerned with temperature control, because higher temperatures produce more of those undesired byproducts, and we don’t use turbo yeasts which commonly throw off more byproducts. So freeze distilling beer or wine made in usual beer or wine fashion should have a lower amount so your health should be at less of a risk. I’ve warned you, so chose to consume freeze distilled products at your own risk.
An additional part of the imperfection is a reflection of how ethanol exists. Ethanol always binds with water in a structure that is 96% ethanol and 4% water. As you freeze distill, you will inevitably catch some ethanol within the ice crystals from the water. However, if you freeze distill over and over again to really boost alcohol content, there will be a point of diminishing returns because that 4% water will start to freeze and trap the ethanol with it. So as you freeze distill down a volume you will inevitably start to freeze more and more ethanol and you will stop concentrating the alcohol you will just be concentrating the flavor.
If one attempted to make an agave wine with agave nectar, water and table sugar and freeze distill it, that person may find fermentation creates an incredibly dry, slightly mead-like, slightly tequila-like product that isn’t very enjoyable. After several freeze distillations, the tequila flavor will start to emerge but it will start to taste sweet, producing something of an agave brandy rather than tequila. After the wine has frozen down from a gallon to about 32 ounces it will have a very noticeable sweet tequila taste and about 25% alcohol. The remaining ice will very clearly have high alcohol content and would taste like watered down tequila. While it may be worthwhile to keep both portions for consumption, the sweet portion would make an excellent margarita at 2/3 agave brandy and 1/3 sweet and sour mix.
The downside to freeze distillation is that it reduces the overall volume of your liquid, so it really takes a lot to make a very small volume of final product. One gallon of agave wine freeze distills down to about 24 ounces of agave brandy at about 25% ABV. That’s less than a quarter of what you would start out with. At that level, it may just be cheaper to buy tequila and save the time and energy.
Concluding Thoughts
I don’t think agave nectar will take a permanent place in my brewing, but it is an interesting and challenging product to work with. I will definitely make another attempt or two at the agave mead to really sort out the recipe. When I do, it will get posted up for sure. I’m positive agave will get some more play in commercial brews but I think there will be a lot of failed attempts because it is so difficult to work with, especially the refined products. Anybody trying to get a really bold agave flavor, especially in a beer, should try to find a less refined product from either a health food store or an online source. That will definitely make finding the right amount to use considerably easy. For mead makers, either source should be worthwhile, depending on how bold of an agave flavor is desired and of course cost. If anybody has good experience putting agave nectar in beer, I’d love to hear about it!!

3 comments:

  1. Thank you so much for posting this information. I have been trying to find information on Agave Mead For Quite Some Time now. I was wondering why it was struggling to ferment and now i know i need to add more nutrient to the mix. I was going to add lime juice concentrate in the secondary. I've found out that it can take up to 60 days for the primary fermentation to be complete. I will share this post with fellow homebrewers. Again thank you.

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  2. Today is my first try at fermenting anything at all. I have 2 one gallon bottles going. One has sugar, all bran, and a handful of seedless raisins. The other has 10 oz of agave nectar, some apple slices peeled, and a handful of seedless raisins. Im using bakers yeast in both.3/4 oz packets.
    I plan (hypothetically of course) to distill in a homemade pot still. Each jar is tubed into a water jar to keep the run clean. I dont have any of the gravity tools or any gauges or anything i probably should have. Im wingin it. Thats how i roll sometimes.
    The batches are alive and very active in jars and the bubbles are flowing out of the tubes.
    Anyway im just joining the flock and hoping for even a small amount of success. If i find where this post is later then ill let you know what happened. Just for the giggling shits.

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  3. Hi there,

    I really appreciate this post. I've seen quite a people trying to brew with Agave, but normally the process isn't explained in very great detail.

    Cheers,
    Greg.

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