Low oxygen brewing

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Low-oxygen brewing (LOB) is a series of steps designed to preserve the fresh flavors of the malt, hops, and other ingredients by minimizing the effects of oxygen in both the hot and cold sides of home brew beer production. These methods are sometimes referred to as "LODO" (LOw Dissolved Oxygen) because DO is a common abbreviation for Dissolved Oxygen.

Thanks to the trendy hop-forward styles like "NEIPA", more and more home brewers are realizing the huge negative impact that oxidation has in the cold side. The same negative impact holds true for the hot side, although fewer home brewers realize the effects of oxidation because it's commonplace for American craft brewers to oxidize their wort.

Low oxygen methods don't necessitate a lot of specialized equipment or ingredients, but they do require attention to detail and refinement of a number of brewing processes beyond the basics. As such, low oxygen brewing should be an endeavor for brewers who already have an understanding of the basic all-grain brewing process. Be aware that it may take several brewing sessions before you achieve success with the whole series of steps to preserve the fresh flavors from start to finish.

For the story about how Low Oxygen Brewing came about, check out the first podcast featuring Bryan Rabe: Episode 01

Deoxygenating the Strike Water

YOS or Pre-boiling are the preferred methods for removing dissolved oxygen (DO) from the strike water. A high dose of sulfite is also effective.

Yeast Oxygen Scavenging (YOS)

Yeast rapidly consume dissolved oxygen, so they can serve to deoxygenate our strike water. The following 2 procedure options are equally effective.

Procedure 1 (heated water, less yeast)

1. Heat the strike water to 90-100°F.
2. Add 1 g/gal of active dry yeast and 1 g/gal of sugar.
3. After the yeast rehydrate, add a physical cap. (See mash caps.)
4. Wait at least 30 minutes.

Procedure 2 (room temperature water, more yeast)

1. Add 2 g/gal of active dry yeast and 2 g/gal of sugar.
2. After the yeast rehydrate, add a physical cap. (See mash caps.)
3. Wait at least 30 minutes.

Yeast will deoxygenate the water in about 20 minutes, but it is prudent to allow extra time to be sure they are finished consuming the DO (unless you can confirm full deoxygenation with a DO meter). After deoxygenation, you may begin heating the water to strike temperature.

Anecdotally, the additional yeast does not have any impact on the resulting wort or beer (neither positive or negative).

Also note: If you let the water continue to sit without significant agitation, the water will stay deoxygenated for at least several days! Therefore, this use a useful method that allows preparation of the deoxygenated water prior to brewing, e.g. the night before.

Yeast appears to have a direct anti-oxidant effect, even after cell death.

Low dough-in temp with active YOS may cause a "weird" flavor.

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Pre-Boiling

Oxygen has very low solubility in boiling water. Therefore, one simple way to remove DO from the strike water is to bring it to a boil.

Procedure

1. Heat the water to boiling.
2. Apply a cap to prevent diffusion. (See mash caps.)
3. Rapidly chill to strike temperature, and capped if possible, to avoid oxygen diffusion back into the water during any time that elapses during chilling and before dough-in.

Sulfite Only (Not a Preferred Method)

Sulfite directly reacts with DO, so it can be used to deoxygenate strike water. This method is not preferred because it affects the water chemistry to a greater degree by adding sulfate and either sodium or potassium, and it relies more heavily on the sulfite being fresh. (See sources of sulfite.)

Procedure

1. Determine the maximum solubility of oxygen at your strike temperature. (How?)
2. Measure your sulfite.
3. Gently dissolve the sulfite in water (crush tablets first if applicable).
4. Add the dissolved sulfite to the strike water several minutes before dough-in, with a brief gentle stir.

Active Oxygen Scavengers

Deoxygenating the strike water alone is not enough to prevent oxidation because the dough-in process can significantly increase DO, and oxygen can diffuse into the wort from the air. Therefore LOB employs additives to actively remove the oxygen that gets into the wort.

• http://www.lowoxygenbrewing.com/ingredients/antioxin-sbt/
• http://www.lowoxygenbrewing.com/wp-content/uploads/2016/12/Antioxidants-and-Flavor-Stability-Translated-Wurzbacher-2011.pdf

Sulfite

When beginning the transition to low oxygen brewing, the suggested starting amount of sulfite in the mash is 20-30ppm of sodium metabisulfite, which equates to 13-20ppm of free SO₂. Sulfite directly eliminates DO. See sulfite usage in beer for more info.

Brewtan B

Brewtan B is an extract of gallotannins. While this product isn't directly an oxygen scavenger, it does help avoid oxidation by facilitating removal of compounds that may promote oxidation and associated flavors.^{[citation needed]}

• BrewTan B dosing

Ascorbic Acid

Ascorbic acid acts by directly with dissolved oxygen and releasing hydrogen peroxide. Suggested usage is to match the concentration to the amount of sodium metabisulfite. Ascorbic acid alone is not useful for scavenging oxygen; it must be used in conjunction with sulfite. See ascorbic acid for more info.

AA and sulfite may work synergistically.

If 100 mg/L ascorbic acid in wine reacts completely with oxygen, 62 mg/L SO2 is required to react with the ascorbic acid oxidation product.

Managing pH

See Brewing pH

...

• http://www.lowoxygenbrewing.com/uncategorized/sulfite-testing-strips-really-need-adjust-ph/
• https://www.brunwater.com/articles/post-fermentation-ph-adjustment
• https://www.brunwater.com/articles/dutching-beer
• https://www.brunwater.com/articles/ph-measurement-temperature
• http://www.lowoxygenbrewing.com/ingredients/a-sauergut-reactor/

Minimizing Oxygen Exposure in the Mash

Coming soon!

• http://www.lowoxygenbrewing.com/uncategorized/wort-recirculation-manifold/
• http://www.lowoxygenbrewing.com/brewing-methods/low-oxygen-brewing-malt-antioxidants/
• tubing consideration
• locline return

Milling

See Milling.

Key points:

• Mill as close to dough-in as possible.
• Avoid shredding the husks.
• Consider flushing the grist with low-oxygen gas (e.g. CO₂) to remove air prior to dough-in. This isn't an absolute requirement, but it is a good tweak after you get comfortable with the rest of the process.

Underletting

Coming soon!

I am milling immediately before dough in and then pouring the grist on top of the strike water. I let it precipitate, or sink in, at its own pace. This seems to me a functional equivalent of underletting, from the perspective of the relative motions of grist and liquor. I end up with the grain nicely dispersed -- I give it a brief stir to confirm, but I find no dough balls at all -- and unlike when I used to stir the grain in rather than just let it sink, I see very little in the way of bubbling and foaming during the process. This indicates to me that the grain is not taking much air down with it. I suppose that if the grist case and headspace could be purged the method would be brought nearer to perfection, but hey, this is one of those points where I let my antioxidants take up the slack. The evidence of the results from the totality of my current process indicates that this is working quite well for me. I pour slowly(ish) but in a single batch. When I'm done pouring there's still a small raft of grain on the surface which gently sinks. It just takes a couple of minutes including a quick homogenizing stir to get all doughed in. Then it's cap on and done.

Capping the mash

Coming soon!

• http://www.lowoxygenbrewing.com/uncategorized/limiting-oxygen-exposure-on-the-hot-side-via-caps/
• https://www.youtube.com/watch?v=CKnVF0CVmRY

Preventing Aeration

Coming soon!

Sparging Techniques

Coming soon!

A tailored batch sparge method is used successfully by some low oxygen brewers.

Low-Oxygen Boiling and Chilling

Coming soon!

• Hops https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2011.tb00472.x
• http://www.lowoxygenbrewing.com/brewing-methods/trub-seperation-why-and-how/
• http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-boiling/
• https://onlinelibrary.wiley.com/doi/10.1002/jib.17
• http://www.lowoxygenbrewing.com/brewing-methods/low-oxygen-brewing-and-hops/

Yeast Management

Coming soon!

• http://www.lowoxygenbrewing.com/uncategorized/oxygenation-of-yeast/
• http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=2&t=1779
• http://www.lowoxygenbrewing.com/uncategorized/lager-yeast-there-has-to-be-an-easier-way/

Fermentation

Coming soon!

• http://www.lowoxygenbrewing.com/uncategorized/lagering/
• http://www.lowoxygenbrewing.com/uncategorized/cold-fermentation-practices/

Dry Hopping

Coming soon!

• http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-dryhopping/

Low-Oxygen Packaging

Packaging is one of the most vulnerable points in the entire brewing prices with regard to oxidation. Preventing oxidation on the cold side is important even for brewers who eschew using a low-oxygen hot side process.

• https://tapintohach.com/2012/06/18/total-package-oxygen-101-measuring-tpo-in-bottle-conditioned-beer/
• https://www.researchgate.net/profile/Anita_Van_Landschoot/publication/293337388_Effect_of_pitching_yeast_preparation_on_the_refermentation_of_beer_in_bottles/links/579cf9ee08ae802facbb976d/Effect-of-pitching-yeast-preparation-on-the-refermentation-of-beer-in-bottles.pdf
• Oxygen ingress during packaging and serving

Gelatin = not needed for clear beer.

• https://www.homebrewtalk.com/threads/weyermann-barke-pilsner-i-made-fire.672018/page-4#post-8890829

Fast Fermentation Test (FFT)

Conducting a FFT is the way we measure the ultimate final gravity of the beer before the batch finishes fermention. This is necessary for spunding.

Shortly after active fermentation has begun, drain 100-200mL (or however much you need to read specific gravity) into a small sanitized vessel (like a flask or jar). Cover it loosely or fit with an airlock, and put it somewhere warm. Continuously stirring the FFT because it will cause a falsely low FG. Some people prefer to avoid stirring it so that the FFT reports the true final measurement. Others prefer to stir it so they can start estimating well in advance when they'll be spunding, and they just assume that the main batch will finish about 0.5°P higher than the FFT. (Your mileage may vary.) It may reduce the offer by spinning the FFTs very slow with a short bar, just barely enough motion to keep the yeast from settling. It's been reported by multiple brewers using a slow stir method that the beer will finish within 1.001 of the FFT.

If if you are brewing ales and having difficulty keeping the FFT warm enough to ferment faster than the main batch, an incandescent bulb in a reflector lamp is useful for keeping it warm. Radiant heat is ideal (for FFTs and yeast starters) because anything blowing or circulating air with dust in it around a loosely foil covered flask may introduce microbial contaminants. Choose bulb wattage carefully, the flask has a greenhouse effect too.

• http://www.lowoxygenbrewing.com/uncategorized/the-easy-fast-ferment-test-fft/

Spunding

Spunding means packaging before the end of fermention, while there is residual fermentable extract. The goal is to package with just enough fermentation remaining to carbonate the beer.

Spunding is the ideal low-oxygen packaging/carbonation method because active yeast help scavenge any oxygen introduced during the transfer, and it avoids using artificial CO₂ that has oxygen impurity.

Process

Determine the ultimate FG with a Fast Fermentation Test, and package when the gravity is 3-4 points above the FG. Frequently measuring and recording the s.g. will help predict the timeframe when the batch will reach the spunding gravity. Making a little graph of the daily gravity readings will help a lot with making accurate time predictions.

Using a refractometer is a good option because of the smaller sample size required. Even though it doesn't accurately measure the density it's fine since we don't really need it. The refraction at bottling just needs to be about 1°Brix above the FFT refraction (when it's finished).

This process isn't as hard as it sounds. The most annoying part is when the beer is are expected to be ready to package in the night or some time when you're away. If you have temperature control it’s gives you another lever to pull to slow down or speed up a little to spund at a more convenient time.

• http://www.lowoxygenbrewing.com/uncategorized/why-do-we-spund/
• http://www.lowoxygenbrewing.com/brewing-methods/fermenter-to-keg-spunding/
• Spunding Automation and Logic

Speise

Speise is German for food; it's what we feed the yeast when packaging.

If spunding is no longer an option because the beer fermented too long, you can add low-oxygen wort that was saved at the beginning. This allows the beer to benefit from the active yeast oxygen scavenging during the natural carbonation process and also achieves proper carbonation.

To save the speise, drain wort (before pitching) from the kettle or fermenter into a sanitized mason-style jar, filling it to the very top (zero headspace). Cap and refrigerate.

When it's time to add it, use a gyle calculator to determine the proper amount. Dump it into the fermenter 15 minutes before packaging.

Kegging

Coming soon.

Basically: Do the FFT and then spund via closed transfer to a purged keg. Consider using a floating dip tube to avoid the yeast sediment.

• A guide to purging
• CO₂ purity and why it's important

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Bottling

Contrary to popular belief, kegging is not a requirement for a low oxygen cold-side process (although it certainly does reduce oxygen exposure). It is possible to drastically limit oxidation with the right bottling process.

Bottled beer ideally should be spunded (see above). However, if you miss the spunding opportunity, priming the fermenter with sugar or speise is the second best option. You should still bottle as close to the end of fermentation as possible. Add the priming sugar or speise, wait 15 minutes (fermentation should be visibly active), and then bottle straight from the fermenter. Spunding reportedly provides noticeably better results than priming.

Bottling tips

• Use large bottles (e.g. 22oz) whenever possible because:
  • It reduces the the amount of beer lost (if you like to leave the sediment in the bottle when pouring).
  • There's less oxygen ingress through the cap relative to the amount of beer in the container (less oxidation).
  • There's less headspace relative to the amount of beer (less oxidation).
• Minimize the amount of headspace by filling bottles to within 1/4-1/2" (1cm) from the top. Less air in the bottle means less oxygen in the bottle.
  • After you fill a bottle, withdraw the bottling wand to the top and gently press the valve against the side of the bottle to fill it higher.
  • Do not fill the bottle completely full because there needs to be a small amount of headspace to prevent explosion if there is thermal expansion.
• Use oxygen-absorbing bottle caps and activate them immediately before or immediately after capping the bottles. Getting them wet is what activates them.
• Keep the bottles reasonably warm so that they carbonate quickly, around 70-75°F (21-24°C) is good.
• Rouse the yeast as often as possible by inverting the bottles and swirling.

Done properly, and with rousing once or twice a day, the bottles will be fully carbonated in 1-3 days! Once carbonated, the bottles should ideally be stored cold. Cold storage slows down oxidation reactions from oxygen that enters through the cap seal. Unfortunately the beer will eventually stale, but, fresh flavors will linger months depending on how well the steps above were followed.

• http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-bottle-filling/
• http://www.lowoxygenbrewing.com/uncategorized/low-oxygen-bottling-methods/
• fermenter priming

Canning

• http://www.lowoxygenbrewing.com/uncategorized/packaging-canning-beer-home/

See Also

Podcasts

• Low Oxygen Overview with WNYBREWS
• http://www.lowoxygenbrewing.com/podcast/

YouTube

• http://www.lowoxygenbrewing.com/forum/viewtopic.php?f=12&t=1787

Articles

• Comparison of Weihenstephaner process with LOB
• Bryan details the build of his brewing system
• Brewing low-oxygen monastic ales and Low oxygen trappist ales
• Hot-side oxygen ingress
• People's Choice test
• http://www.lowoxygenbrewing.com/uncategorized/basemalt-blending/

Potential sources

• https://www.homebrewersassociation.org/forum/index.php?topic=27965.0
• "Effects of Sulfur Dioxide and Polyvinylpolypyrrolidone on the Flavor Stability of Beer as Measured by Sensory and Chemical Analysis"
• "The influence of unmalted barley on the oxidative stability of wort and beer"
• Lipid changes during storage of milled hulless barley products