Low oxygen brewing

Low-oxygen brewing (LOB) is a series of steps designed to preserve the fresh flavors of the malt 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.

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.

YOS option 1 procedure: 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 Capping.)
4. Wait at least 30 minutes.

YOS option 2 procedure: 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 Capping.)
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 (either positive or negitive) on the resulting wort or beer.

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 some kind of direct anti-oxidant effect. It's unknown whether this has any impact on protecting the wort. Could this be related to vitamin E?

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 Capping.)
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.

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.

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.

Managing pH

Coming soon!

• https://www.brunwater.com/articles/post-fermentation-ph-adjustment
• https://www.brunwater.com/articles/dutching-beer
• https://www.brunwater.com/articles/ph-measurement-temperature

Biological Acidification

Coming soon!

Minimizing Oxygen Exposure in the Mash

Coming soon!

Conditioning and Milling

Coming soon!

Underletting

Coming soon!

Capping the mash

Coming soon!

Preventing Aeration

Coming soon!

Sparging Techniques

Coming soon!

Low-Oxygen Boiling and Chilling

Coming soon!

• Hops https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2011.tb00472.x

Yeast Management

Coming soon!

Fermentation

Coming soon!

Dry Hopping

Coming soon!

Low-Oxygen Packaging

Coming soon!

Fast Fermentation Test

Coming soon!

Spunding

Coming soon!

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 fairly easy to drastically limit oxidation with the right bottling process.

Spunding (packaging with residual fermentable extract) is always the ideal method, combined with bottling straight from the fermenter. Determine with ultimate FG with a Fast Fermentation Test, and bottle when the gravity is 3-4 points above the FG.

If/when you miss the right spunding gravity, priming the fermenter with sugar or speise after fermentation has completed is the second best option. However Spunding reportedly provides noticably better results.

Bottling tips

• Using larger bottles (e.g. 22oz) is helpful because there will be more sediment, there's less oxygen ingress through the cap relative to the amount of beer in the container, and there's less headspace relative to the amount of beer.
• Minimize the amount of headspace by filling bottles to within 1/4-1/2" (1cm) from the top.
• Use oxygen-absorbing bottle caps and activate then immediately before or after capping the bottles. Getting them wet is what activates them.
• Keep the bottles reasonably warm and that they carbonate quickly, around 70-75°F (21-24°C).
• Rouse the yeast as often as possible by inverting the bottles and swirling.

Done properly, the bottles will fully carbonate in 2-3 days. Once carbonated, the bottles should ideally be stored cold.

Saving speise

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

Ideally you can add low-oxygen wort that was saved at the beginning so you can still benefit from spunding and also achieve 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. To add: use a gyle calculator to determine the proper amount. Right before bottling dump it into the fermenter and gently stir to make sure it's distributed.

• 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