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Gluten Free Home Brewing Blog

How Ondea Pro Works: Some Preliminary Thoughts

By Aaron Gervais, co-founder and head brewer at Otherwise Brewing  -  March 11th, 2020

Shared with permission by Otherwise Brewing

Ondea Pro is a pretty exciting development for gluten-free brewing, and over at Otherwise Brewing, we’ve been experimenting with it a lot. As such, I wanted to add some insights to complement the excellent primer that Jason Yerger and JP Bierly put together in January.

We’ve seen some results that match up with what Jason and JP have found, but we’ve also seen a few differences. I’ve also conducted a number of controlled mini-mash experiments to try to track down the mechanisms involved.

What follows is my understanding to date of what Ondea Pro is doing in our beers. Hopefully this will be useful in your own brewing as well!

Extract efficiency and fermentability

You don’t need Ondea Pro to hit 28 or 30 PPG with rice malt. I was hitting those numbers with Termamyl before I ever got my hands on Ondea Pro. I’ve tried a number of different mashing regimes with the enzyme, and the change in extract efficiency is small, maybe in the range of 5% or less.

So what’s going on? I’ve found that the key to mashing rice is a high-temperature rest. It takes at least 60 minutes to “cook” rice all the way through at temperatures in the 170-190°F range. You can do that rest entirely up front, or you can split it up into a shorter preliminary rest and a longer mash-out/vorlauf rest. Both methods work to extract starch from the grain.

That said, Ondea Pro does make your wort less viscous so that it’s easier to lauter. It also slightly increases the fermentability of the wort, though not nearly as much as a saccharification enzyme would. The most likely reason for this increased fermentability is the pullulanase enzyme in the cocktail, which reduces the number of amylase-resistant limit dextrins.

Looking at identical mashes with Termamyl alone vs. Termamyl + Ondea Pro, I’ve seen fermentability move up from the low 30% range to the low 50% range.

Fermentability of Various Mini-Mash Tests Using Pale Rice Malt

Rest 1: 185°F

Rest 2: 140°F

Mash-Out: 170°F

Total Mash Time


30 min Termamyl



30 min


60 min Termamyl



60 min


120 min Termamyl



120 min


30 min Termamyl

45 min Ondea Pro

30 min

105 min



45 min Ondea Pro

60 min

105 min


25 min Termamyl

60 min Ondea Pro

60 min

145 min


That’s still definitely on the low side for an all-grain brew, but if you’re doing a partial mash with added syrups/sugars, it might be just about right. However, if you’re brewing all-grain and looking for suggestions on increasing fermentability to more normal levels, check out my article Enzymes for Gluten-Free Brewing.

Flavor improvements

Many brewers have remarked that using Ondea Pro does away with celery seed/wintergreen off-flavors in their beers. This is another area where I’m going to say Ondea Pro is not strictly necessary, although it does seem to help.

I have never had any of these off-flavors in my rice beers, using Ondea Pro or not, though I’ve tasted them in other people’s brews. I suspect that the culprit is insufficient yeast nutrition. Part of the Ondea Pro cocktail is a protease that releases yeast assimilable nitrogen (YAN). It’s possible that the malting process for rice does not naturally release enough YAN for good yeast health and that Ondea Pro steps in to correct the balance—the product datasheet does specifically call out Ondea’s ability to increase the amount of YAN in wort.

I know that most GF brewers are using yeast nutrient already, but you may not be using enough. When I first started with gluten-free brewing, I used FERMAX simply because I had some lying around. Upon further research, however, it seems Fermax is targeted more toward cider and wine makers, so it has higher dosage recommendations than most of the beer nutrient brands out there.


Dosage Rec.’s (g/gal)

Dosage Rec.’s (ppm)




Yeastex 61



Fermaid K




(“High Risk” dosage)

1.9 Superfood

2.1 DAP

500 Superfood

500 DAP


(“Very High Risk” dosage)

2.3 Superfood

2.45 DAP

600 Superfood

650 DAP

All of these nutrients are similar in that they provide a certain amount of DAP as well as autolyzed yeast and trace vitamins and minerals, so the biggest impact in varying the dosage will be total YAN content.

Even from a winemaking perspective, FERMAX’s recommendations seem ridiculously high. I eventually cut down my usage to closer to 750 ppm for all-rice beers and did not experience any off-flavors. Now that we’re scaling up for launch, I’ve upgraded to a more premium nutrient, BSG Superfood, used in combination with DAP at the High Risk or Very High Risk dosage levels. So far, no off flavors, though to be fair I haven’t tried Superfood without Ondea Pro yet.

Head retention and body

Head retention and body definitely improve with Ondea Pro, and the most likely explanation is that a number of Ondea Pro enzymes are working synergistically together:

Protease: As mentioned above, the protease increases YAN, but protein in beer is not a one-size-fits-all situation. The smallest building blocks, free amino nitrogen (FAN), make up the majority of what the yeast consume. There are also large proteins that survive the mash and end up in the boil, where they combine with phenols to turn into hot break. Finally, medium-sized proteins make their way into the finished beer and contribute to both body and head retention. As I’ve written about in my article on cereal grain anatomy, this lack of protein is probably the reason why GF beers feel lighter on the palette than their barley equivalents of the same gravity.

Lipase: Grain-derived oils are generally not beneficial in brewing, and Ondea Pro has enzymes to break them down. Some of these grain oils can lead to staling and lack of head retention, so having an enzyme to break them down should help.

ß-glucanase and xylanase: These enzymes degrade cell walls within the grains, making their contents more accessible. Left untreated, cell wall fragments make the mash gummy, hurting lauterability and possibly leading to problems with haze and beer stability (again, see cereal grain anatomy article). However, when these components are broken down, they have a beneficial impact on lauterability, yield, and head retention—at least for barley brewers who do a traditional ß-glucan rest at around 105°F. In Ondea Pro, we have the benefit of much more heat-stable ß-glucanase and xylanase that survive up to about 155°F. So we get all the benefits of a ß-glucan rest without the extra temperature rest.

Unrelated to Ondea Pro, one other tip to improve head retention, courtesy of Jim Eckert, is to use a certain proportion of biscuit malt. Jim does this in all of his beers, which are 100% rice malt, and he gets good, long-lasting foam on them. I also find a larger proportion of biscuit malt leads to a clearer wort. The why of it all is a bit of a mystery. My best guess is that something about the malt roasting process affects rice proteins in a beneficial way, but it will take some more rigorous scientific testing to truly figure things out.

Suggestions for usage

With all that in mind, here are a few tips for getting the most out of Ondea Pro with rice malt:

● Do a partial or complete pre-cooking of your rice prior to adding the enzyme. In my mini-mash tests, Ondea Pro did not provide any benefits to yield or fermentability when added to non-gelatinized rice malt.

● Dose Ondea Pro at between 0.6-1.2 ml per lb of grain. That works out to the 50% and 100% dosage recommendations provided by the manufacturer. You may be able to get away with much less, but there are so many variables involved, I haven’t had time to really test what the lower limits are.

● Add Ondea Pro to your mash no hotter than 145°F. Some of the key enzymes start to denature above 150°F, and most of them work best between 120-140°F.

● The protease and lipase work best at around 120°F while the xylanase, ß-glucanase, and pullulanase all work best around 140-145°F. Try splitting the difference temperature-wise, or slowly raise it through both ranges over the course of an hour.

● Conduct a mash-out at 170°F or higher, especially if you only partially cooked your rice at the start. This will denature the non-amylase enzymes and give the liquefaction enzyme time to extract any remaining dextrins at its ideal temperature.

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