GF Substitutions Part VII: All About Starches

by Jenn on August 24, 2010

in GF Substitutions,Gluten Free

Welcome to the next installment of Gluten Free Substitutions here on Jenn Cuisine!  We are now really getting into the nitty gritty of gluten free ingredients, last week covering binding agents, and this week moving on to the starches.  I think you’ll find this week is a bit easier, less complicated chemistry, hopefully :) The binding agents really did need chemistry though, because their main purpose in GF baking is to replace the missing properties of gluten.  Starches also can have some binding properties, albeit to a lesser extent.  I promise to keep the chemistry a bit less this week…we’ll see how I do 😉

Typically isolated starches, mostly or completely devoid of protein content and almost flavorless, can dissolve in water when heated, which is great for sauces that you want to be thickened, but you don’t want any flavors from the flour – or maybe you want a clear gravy.  Flours often have some starch content but also have other things as well (like protein!).  Often in GF baking recipes there is a starch listed in the ingredients, so I thought it’d be good to take a look at exactly what that starch part is – is there a reason for using a pure starch in your GF flour mix?  What exactly is the purpose of starch anyways? Here, let’s take a look at two extremes – tapioca starch and white corn flour – (And yes, I have a beaker for a measuring cup, I am a full chemistry nerd!).  Tapioca starch is clearly a starch, where as the white corn flour is indeed a flour.  Corn does contain starch, but it has to be extracted out of the corn to get pure cornstarch.  Here, I’m just talking about the flour – just finely ground up corn.

First, I added water to see what happens.  Side by side it looks like the corn flour dissolved better – see how much clearer the water is?  But look closely, and you’ll see that it pretty much all settles out to the bottom.  However, the tapioca is white like milk.  We find that the corn flour stays completely gritty if one reaches their hand in and tries to pick up the flour bits, where the tapioca mix feels like liquid only.

White corn flour in water:

Corn Flour

And tapioca flour in water:

Tapioca Starch

But don’t be fooled, actually neither dissolved! My tapioca starch is much finer than the corn flour, so the little particles have no problem floating around throughout the liquid (called suspension) where the heavier corn flour particles just sink to the bottom.  So neither really dissolve well in cold water.

OK, so now comes the fun test – what happens when we heat them?  First, the corn flour – upon heating and then cooling, the flour/water congeals to what looks like a precursor of porridge….

Corn Flour

And while it certainly has thickened, there’s no real gooeyness – if you pick it up with the spoon it just breaks apart from itself.  There’s not much really trying to hold it together.  Now I did the same with the tapioca – Upon heating, the tapioca all dissolves and turns clear and is a bit gelatinous.  See those air bubbles trapped?

Tapioca Starch

I did the same with sweet rice flour too, which is also very starchy.  When heated, it turned to a whitish/gray goo instead of clear, and I don’t think it was quite as gel-like compared to the tapioca.

Ok, I know what you’re thinking – “Thanks for the science lesson and all….but what does this have to do with my gluten free baking?” Alright, I admit it’s not so obvious just yet – but take another look at the tapioca starch concoction.  Look at how thick it is – see how it’s rounded up near the bottom of the spoon?  That shows surface tension and viscosity – And when you pour it from the spoon you get an “ooze” that slowly falls off the spoon to the bottom on one long strand.  Oh I know that sounds so appetizing, ha!  But those properties are there when you bake, and are part of what helps things stick together.

Tapioca Starch

But starches are not as strong as the gums or other binding agents.  And add too much of them, and you end up with a gooey mess.  Don’t make a cake with only starch.  It won’t be pleasant.  However, when I make gluten free pasta by hand (especially if I am going to be molding it and stuffing it), I have a very high starch content in my flour mix in order to keep the dough together: about 75/25.  But usually there is no hope for reheating the next day, because after a night in the fridge it has definitely congealed into a rather unattractive impossible to separate glob of goo (though I have had good luck freezing before cooking).   However freshly cooked, no problems, quite exquisite.

When I am making a GF recipe, I think about my starch:flours ratio.  Usually for goods such as breads, muffins, any type of dough (besides pasta) really, I aim for about 1:2 starch:flours – that means about 1/3 of my GF mix for a particular baked good is made up of a starch.  Then I tweak from there, depending on how things are going.  I have no idea if this is a normal amount, it’s just what I’ve tended to use.  If Michael Ruhlman could write a 2nd version of his best-selling Ratio book for gluten free recipes, I would love to see what the ideal ratios of flour mixes are for each type of good.  Is there a ratio of starch:flours that works best for you?  Have you found the amount of needed starch to change depending on what you are making?

So which of those gluten free ingredients are starches? I’ve typically come across five:

• Tapioca starch
• Potato Starch
• Arrowroot Powder
• Corn Starch
• Glutinous Rice

Is one starch better than another in certain situations? Maybe.  Def. in sauces/cooking applications they have differences.  But when it comes to baking, I’m not really sure.  In my experience I haven’t really noticed a difference between using one or the other.  But then, my baking experience is not so comprehensive as of yet.  We typically use tapioca, because I can buy it cheaply at our local Asian foods store.  We’ve tended to stay away from corn starch because of my father-in-law’s corn issues – not sure if the corn starch would affect him, but better to play it safe and use something else.  Maybe some of you more experienced GF bakers can chime in here: Does the end-quality depend on which starch you use in a recipe?  Are there reasons why you prefer one over the other in baking?


Rosa August 24, 2010 at 10:22 am

Those are very practical.



Jenn August 24, 2010 at 6:08 pm

Thanks Rosa! I hope it is!

Deanna August 24, 2010 at 3:15 pm

I LOVE that include all the science stuff. That’s the best part! :)

As for which starches work best, I’ve found that we don’t like the flavor of tapioca starch much. My husband can sniff it out from a mile away, I swear. So, unless what I’m making has a very strong flavor, I avoid it. That’s sort of a bummer because it is definitely the cheapest.

We tend to use arrowroot for recipes that have a high starch:flour ratio.

I’ve found that for most cookies and pancakes, I can omit the starch entirely if I’m using sorghum flour and some other source of moisture – like peanut butter or banana or apple sauce. The end result is not as light and fluffy, but is much more nutritionally dense and “whole grain” tasting – which is how we prefer things.

Jenn August 24, 2010 at 6:09 pm

Very interesting! I’ll have to try this with my peanut butter cookies that I’m working on….

carrie @ August 24, 2010 at 4:22 pm

This is a wonderful post on the use of GF starches! I love how thoroughly you delve into this! In my kitchen for pure simplicity I use one starch. Arrowroot starch. That’s it. It seems to work really well in whatever I’m baking or cooking! I have intolerances to corn, I don’t like the taste of tapioca, and potato starch is well… too high on the glycemic index for my body… so arrowroot takes the cake at our house! :-)

Jenn August 24, 2010 at 6:20 pm

Hmmm maybe I don’t have a great palate, I honestly can’t taste the tapioca starch in baked goods. Maybe it is not as flavorless as I (or my husband) thought!

As to the glycemic index.. is there really a significant difference in the glycemic index of arrowroot powder compared to potato starch?? I can’t seem to find any numbers online, so I’m really curious how big of a difference this is – I would expect both of them to be rather high since starches are essentially complex sugars… But that is really interesting if there is a difference!

fooddreamer August 24, 2010 at 4:46 pm

Wonderful, wonderful information. I can’t do too much of the starches because of my blood sugars, but it’s so good to know all this if I ever am baking just gluten free. Thanks!

Jenn August 24, 2010 at 6:22 pm


Barbara | VinoLuciStyle August 25, 2010 at 12:38 am

Jenn, I admit I don’t have to follow a gluten free diet but a friend of mine does; so I find this information interesting and have shared your blog with her. It’s much appreciated!

Jenn August 25, 2010 at 1:12 pm

Thanks Barb! I hope it’s helpful!

InTolerantChef August 25, 2010 at 12:41 am

I really enjoyed this subject. I like to know why things react a certain way. I love my Ratio cookbook, and wouldn’t it be fantastic if there was a gluten free one…It would be like cheating! All the hard work done for us. The good thing about ratios is that they are just the bare bones of the recipes, you then get to flesh them out however you like and it’s where the creativity comes in. Great job.

Jenn August 25, 2010 at 1:12 pm

Thanks! Yes, I think there does need to be a gluten free version of Ratio!

Maggie August 25, 2010 at 3:18 am

This is my favourite of your series! The starches amaze me and I would love to never bake with them again – because they’re so white and starchy! Alas, they make GF baking so much easier. I find it amazing that Elana from Elana’s Pantry almost never uses starches. It’s that glycemic index thing again! I would love to know the difference between potato and arrowroot too Jenn. So if you find out, let me know! I still haven’t come up with a set ratio. I tend to guesstimate when I’m working on a recipe and it has so far worked out well. I have subbed out starches with coconut flour and it was a little more dense with less rise, but still good. Gosh, I’m rambling now! Thanks for another great post!

Jenn August 25, 2010 at 1:31 pm

Thanks Maggie! Will def. let you know if I find anything on GI’s of starches, though I think we should be asking Carrie :) You’re right, Elana only uses almond flour in so much of her baking – and all her stuff looks gorgeous. I haven’t made very many of her baked goods recipes, perhaps I should try out some more!

Anna Johnston August 25, 2010 at 7:12 am

Fantastic information. I’ve forwarded this onto a friend who I know will get heaps out of this too.

Jenn August 25, 2010 at 1:32 pm


Heather August 28, 2010 at 7:26 pm

I always learn so much from you, whether it’s from a recipe, a photograph, or this substitutions series. Thank you!

Jenn August 28, 2010 at 7:33 pm

You’re welcome! I’m glad it’s informative!

Sophie August 30, 2010 at 6:06 am

I am living gluten free since june 2010 & I am loving it but I still need to learn a lot! This was very useful too!

You explain everything so good! I RSS ed you!!

Thanks & many greetings from a fellow gf fan from Brussels, Belgium!

Jenn August 30, 2010 at 7:22 am

Thank you, I’m glad it is helpful! I just think it’s important when we are all going into baking with all these “new” ingredients, that we try to learn a little bit about the ingredients and their function. It has definitely been a learning process for me as well!

Christin September 27, 2010 at 6:46 pm

Thank you for the good information. We are a GF household, but until last week were able to do corn. Just figured out that any corn product causes our daughter to react as much as wheat. Would you say that tapioca is the best substitute for cornstarch? I have a great flour recipe with cornstarch, and am trying to figure the best alternative.

Jenn September 27, 2010 at 7:30 pm

Your welcome! Yes, tapioca starch should work fine replacing corn starch in baking. According to this article by Amy of Simply Sugar and Gluten Free, corn starch may not produce the most ideal qualities in baking anyways, so your GF goods may in fact be better off by switching to tapioca! Good luck and may you have many more happy GF baking experiences!

Caitlin April 16, 2011 at 2:36 pm

Wow – How lucky is your father in law!

T.R. Crumbley July 6, 2011 at 5:30 pm

Such a useful blog post! I have a few friends asking for this so thank you! Definitely sharing…

Lois Parker July 19, 2011 at 2:00 pm

Interesting experiment. I use tapioca flour in my gf cooking all the time. It is 40% of my usual flour mix (the other flours are 40%urid lentil and 20% cornmeal). I also use it pre-gelatinised in things like pasta and flatbreads as it allows for very thin pasta to be made and flatbreads not to crack when rolled. I just take 100ml water, 10gm tapioca, mix when cold and cook until clear and add to the recipe (takes a bit to effort to mix)

Jenn July 19, 2011 at 6:36 pm

thanks! where do you get lentil flour? that sounds interesting!

Lois Parker July 19, 2011 at 7:04 pm

I get it at Spices of India ( or com..can’t remember off hand. If I lived in a town with Indian shops I could probably just buy it there. It is also called Papad flour; it is used with urid rice to make papadums, dhosa etc. Southern Indians make many steamed buns with this combination as well.It adds a lot of protein, low gi, and crucially, means you don’t need any gums in gf cooking and it can pretty much be swopped direct for wheat (bit of tweaking) except in yeast doughs. It doesn’t add any weird flavour or colour, which is a problem with things like chick peas.
I have talked to Shipton Mill about making my flour mix available, they are hoping to have their new gf facility operational by the autumn. Once that is working it will be a lot easier for people to make use of my many hours of experiments!

Gavin February 27, 2012 at 9:51 pm

I personally try to limit my usage of starches as much as possible, trying to use grain flours at the highest ratio so I can get the benefits of protein, iron, vitamins, etc. I usually just use mostly sorghum flour, some brown rice flour, and xanthan gum. But for the occasion recipe where I feel a starch is necessary, I use tapioca or arrowroot starch. I don’t tend to notice much difference between them. Also, chia or flax have great properties that can help reduce starch use.

Elisa October 13, 2012 at 5:38 am

Like Gavin I try to limit starches too but would LOVE to know how to replace starch with a non starch in baked goods. Any ideas would be fabulous! I currently use buckwheat, quinoa, amaranth, some millet and nut flours in my baking but need something to act as a starch….hmmmm

Jenn October 13, 2012 at 3:51 pm

Hmm… have you looked into Elana’s Pantry? She has a lot of recipes that use only almond or coconut flour…

Adnan Ahmad January 13, 2013 at 5:45 pm

my project is on starch blend with inorganic material. and its really helps me a lot
thnx alot

Kay February 10, 2014 at 10:59 pm

For those of you who are afraid to use starches because of high glycemic index, try using resistant starches like raw potato starch or high-maize corn starch. These tout the benefits of starches, but are non-digestible until the lower intestine providing lower blood glucose responses and benefits to colon health. One cautionary note: the resistance of starches can be modified depending on how and whether they are cooked. For example, raw potato starch is good for non or low heated items, but will gelatinize at high temperatures, causing it to lose its resistant qualities. Cooking starches in a moist environment (e.g. steaming or boiling) causes starches to lose more of their resistance than cooking in a dry environment (eg roasting). High maize cornstarch is better for cooked items as it is more resistant to such effects at higher temperatures.
I am a type 1 diabetic and have been experimenting with resistant starches for the past year or so. Bean fours are high in resistant starch and are great thickening agents. Green pea flour makes excellent chocolate chip cookies. I add raw potato starch to fruit smoothies in order to reduce the glycemic load of the accompanying fruit and take advantage of the “second meal” effects (consuming resistant starches at one meal has been shown to reduce glycemic response at the following meal). I use high maize cornstarch in quantity in many baked items from cookies to breads, even puddings. I also try to take advantage of naturally occurring resistant starches like green bananas instead of ripe, raw vegetables instead of cooked (the cooking process gelatinizes the sugars, making the starches higher glycemic index), and cooked then cooled rice, potatoes, and pasta (the cooling process converts some of the gelatinized starches back to resistant starches).
I have measured the glycemic effects of many combinations of manufactured flours & starches, as well as naturally occurring starches using a continuous blood glucose monitor. Therefore I can personally attest to the benefits of resistant starches in lowering glycemic response. Being gluten free and type 1 diabetic is a particular challenge since many of the GF products on the market use rice flour and starches which have very high glycemic index. However, I have found that combining rice, nut, and legume flours with resistant starches rather than corn starch has afforded me many more healthy options! It has been a lot of work, and I am still at it, but thus far I have gathered a lot of practical information that helps me reduce postprandial blood glucose.

Jenn February 11, 2014 at 7:51 am

Thank you for such an informative comment! I am definitely interested in researching more about the specific glycemic effects of each type of starch and will be doing a bit of reading now :)

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