How to make your own GU

Update - 1/29/2001

I was frustrated with my own "gu-style" energy gel, lacking in the following ways: 1) It destabilizes after a period of time, becoming more solid and cloudy 2) It has an unpleasant taste because of the maltodextrin, which can be somewhat masked by small amount of alcohol, but not completely. So, I thought, hey, why not ask GU how they do it. Got nothing to lose. Here was their response:
Philip,
Thanks for your interest in our product. Of course your questions are of a proprietary nature, so I will not be able to answer them. However, I can tell you that we put three years of extensive product development into GU Energy Gel before we introduced the product in 1993, and that the formulator of GU is a Ph.D. bio-chemist with over 30 years of research experience. We've applied so much understanding and effort in developing a product that has a shelf-life of more than five years with no harsh aftertaste.
Please don't get sidetracked, the power behind GU is not simply the carbohydrate content, but the branch-chain amino acids, muscle buffers, anti-oxidants, and the herbal blend. The performance benefits of GU are quite remarkable.
Best regards,

Brian vaughan
President, Sports Street Marketing

And though it's not as good, I asked Powergel the same question, eventually replied:

Dear Phil,

Thank you for contacting Power Bar on the Internet. We welcome questions and comments from our consumers.

Good questions regarding maltodextrin. Unfortunately that information is proprietary and not available for public distribution.

We appreciate your use of our products and hope that you visit our web site often.

Sincerely,
Joel
Consumer Relations

Mmm... GU. Gooey carbohydrate gel. I used to think it was kind of silly. But the real reason I never tried the stuff is because it was expensive. 1$ for 100 calories. Yeesh! Makes for expensive trips. But noted "extreme" alpinist Mark Twight swears by the stuff, so it made me think. Then in preparation for our Liberty Ridge climb, which is about as close to "extreme" as I've come, I brought the topic up, and my friend Marcus excitedly spoke of the wonders of GU. I wanted any help I could get for Lib Ridge, so GU I bought. And on summit day, GU I ate. I was great... I really didn't have an appetite for anything else, and it kept my energy levels high (or at least higher than I had expected) throughout the climb. Seems to work!

However, I realized that feeding my GU addiction would be expensive... so I set out to make my own.

Quantities

The basic ingredients for the maltodextrin-based refined stuff:

Malto-dextrin - available at brew stores. This is the bulk of GU, so make sure you get it cheap. I found it for as little as $1.65/LB, and as much as $4/LB. Usually comes in 8oz packages, or 5LB bags. Maltodextrin is a refined complex carbohydrate, made from corn, that doesn't taste like much. It comes as a white powder, and turns very gummy when mixed with water (hence GU).
Water - comes from your tap.
Fructose - A kind of refined sugar. Not that easy to find, but I think most grocery stores have it, as it is used by diabetics. You can use other types of sugar too. But fructose has a very low glycemic index, so it doesn't cause spikes in your blood sugar. Regular table sugar has a high glycemic index. Maltodextrin has an extremely high glycemic index, so fructose helps balance it. I've seen fructose in little packets (annoying), and in half pound bags, put out by the same company that makes all those specialty flours in little bags. If you can't find it, use table sugar, but beware the sugar high! I've used other more natural sweeteners like maple syrup, but those impart a flavour to the GU, and will overwhelm any flavouring you add.

Ok, and then you'll need salt, pectin (available in jam-making section of grocery store), and citric acid (brew store). I'm not sure how important all these ingredients are - they probably don't make a big difference, but they are in GU. Finally, you'll need some sort of flavouring, and possibly some booze. Yes, really, some booze!

Quantities and Procedure

The basic ratio of complex to simple carbs in GU is about 4:1. So mix together 4 parts maltodextrin with 1 part fructose. Then, add about 2 parts water and stir this all together over low heat on the stove. Actual GU only has about one part water, but to get this to work (i.e. for the maltodextrin to dissolve), you need more than that. I think some of the water evaporates as you're heating it anyway.

At some point, add the other stuff (salt, pectin, citric acid to taste, and flavour). Use a "pinch" of these. And if you want to totally simulate GU, add some anti-oxidants (vitamin C and E), and some amino acids (GU has valine and leucine). Hard to find this stuff in easy to dish out format though. These promote muscle recovery or something.

And finally, potentially the most important ingredient is a little booze. Let me explain. My first batches of "GU" came out tasting pretty good. I used orange and almond extracts, which were alcohol-based. Later on, using other non-alcohol extracts, my GU came out tasting like crap. Good at first, but then with a weird, bad aftertaste that some described as metallic. What was it? It's the maltodextrin, which starts tasting kind of weird after you heat this mixture (actually, I don't think it matters if you heat it - but you can't detect this taste if you just eat the stuff dry). I became pretty sensitive to this "off" flavour, and began to find it pretty revolting.

Then I made another almond batch, and it didn't have this taste. Hmm... could it be the alcohol, I thought? So I made a grapefruit-flavoured batch (where the flavour didn't have any alcohol), and I added a little gin (just a bit) to it. The bad taste was absolutely gone! I don't know what's going on here chemically, but it seems to work. I don't know what GU uses to get rid of this taste, because there's no alcohol in their stuff.

Keep stirring. Maltodextrin is hard to dissolve. There will be little white chunks left. Keep stirring, but you probably won't be able to get all of them. Finally, pour into a food squeeze tube (available at your favourite outdoor store). Sealing these tubes (at least the Coghlan's brand) it a pain in the ass, but it gets easier the more you use them.

Problems

Getting the right consistency is hard. And the stuff seems to "de-stabilize" after a while, and turn harder (more chewy, instead of gooey :-). Perhaps there is some missing ingredient that keeps stuff together. More pectin? One of the preservatives in GU? Who knows. Putting it in the fridge seems to accelerate destabilization.

The "product" should turn out pretty transparent once your pour it in to the tube. And then it may get even more clear. But by the next morning, it will be an opaque white again. At least that's what I have found.

Flavours

You can of course get orange, vanilla, and almond extracts at any grocery store (mint too, but it doesn't go well in GU). And a bunch of artificial ones too. But go to Nature'sFlavors.com and you're in flavour heaven! They've got hundreds of "flavours", all of which are apparently natural (however... they aren't necessarily from the fruit in question... for example, I don't think pear flavour is necessarily pear extract... it's a bunch of stuff that kind of tastes like pear). The flavours are extremely concentrated, and don't seem to be based on alcohol. It's just... flavour. Kind of weird. But the price is right. 4oz bottles are about 5$, and that'll probably be enough for several hundred GU-packet-equivalents. The stuff is concentrated.

I also think these flavours would be a good alternative to artifically-flavoured sugar drinks like gatorade. Just take some in a little plastic bottle, and mix some in your waterbottle with some sugar, and voila, all natural fruity drink.

Other carbohydrate gels

I've also used brown rice syrup, which is what ClifShot's are made from. This is like, the organic, natural version of GU. Probably better for you. Brown rice syrup is about 60:40 complex carbs to simple carbs. Available at your favourite organic health food type store. Not too expensive, but not as cheap as maltodextrin.

The problem with this is the only brown rice syrup I've used, has imparted too much of a flavour to the GU. Perhaps that's why ClifShots have strong flavours like chocolate, coffee or peanut, instead of the fruity flavours that you can get with GU or PowerGel (both based on maltodextrin). They need it to overcome the "whole wheaty" flavour of the syrup. Anyways, using brown rice syrup is much less of an experiment in chemistry than maltodextrin. Just mix your flavour with it. Done. The stuff is kind of messy though.