I wrote up some of my thoughts on oxygen reduction prior to mashing at our site:
http://www.lowoxygenbrewing.com/uncategorized/examining-oxygen-ingress-pre-boil/
Initially, I poo-poo’d the thought of pre-boiling my mashing and sparging water. I figured at the 150F+ water temperature, the oxygen content of 4 ppm was no big deal.
Then I went ahead and checked the chemistry and performed the mass balances for the various phases of our brewing processes. I found out pretty quickly that when you are doing things like avoiding too much mash mixing and including a mash cap, that hot water’s 4 ppm oxygen content ends up being a MAJOR percentage of your oxygen budget. That means that I was needing to almost double my SMB dose to account for that un-boiled water’s oxygen content. So, pre-boiling or conducting some other form of de-oxygenation is an important aspect of reducing your total SMB dose.
The other thing I recognized was that SMB does contribute a significant sulfate dose to your water and you do need to account for that. In essence, every ppm of SMB that you add to your water, you’ll end up adding slightly more than a ppm of sulfate to the wort. If you are dealing with a ‘leaky’ system and need to dose SMB a bit higher, that extra sulfate can really dry out your beer more than you want.
SMB treatment is a great technique, but do those other measures to reduce your need to dose at elevated levels.
Martin, any plans to include meta in Bru’n Water?
Great insights Martin.
If people were to take advantage of the slight workaround I detailed, it would be with the knowledge that a mash cap, reduction of agitation, etc. we’re already in effect. You’d want to target something a bit above mash temps as well. Something like 185 °F reduces DO to about 2.3 ppm.
Also, it’s important to note that someone like me doesn’t add Sulfate so the amount I get is purely from my antioxidant dose.
With that said, I’m not ready to stop preboiling as it is my SOP. It nice to know that in a pinch I could target a temp lower than boiling and account for that up front.
You know, there is a spreadsheet that has all that stuff incorporated…
I resisted the idea of preboiling at first too, Martin. Glad to be doing it now.
Could one pre-boil the night before? I know most (me) are concerned about length of brew day…
Nope, you will be back at scratch within a few hours.
I was hesitant at first to add another step, but pre-boiling really doesn’t add all that much time as long as you have a decent chiller. At this point it seems easier to me than attempting any alternate methods of water deoxygenation (yeast + sugar scavenging, for example).
I agree.
I have a bucket heater on a timer to get the water up to 170F or so before I wake up, then it takes about a half hour to get to the boil. 10 gallon batches.
Yes, the next supporter’s version will have SMB in it.
I’ve been using the yeast method. I brew outside, so I figure by the time I wheel the kettle to the garage and cool it down, I would be back at square one.
It works well. I own an Extech DO meter and actually measured slightly lower strike water DO with yeast + sugar than pre-boil (but that was only 1 or 2 tests).
That being said, now I primarily pre-boil. Just as easy on my current setup and eliminates any concerns about the dead yeast.
I’ve done it both ways many times and I feel that DO by boiling probably produces a slightly cleaner beer but the yeast DO method is WAY better then nothing at all. The benefits to YDO, as were mentioned… it’s dead simple, can be done in advance since it will hold and it’s more energy efficient. Also it’s probably faster then boiling and cooling depending on how big your burner is.
I perform full volume no-sparge beers (6 gallon batches) and with a typical 8.5-9 gallons of water to heat up it usually takes about 50 minutes to get to a boil. After the quick 5 min boil, it only takes about 5 minutes or so to bring it down to strike temps.
During the wait for the boil I take care of measuring out my salts, antioxidants, condition my grains, and mill them. My total brewday is always under 5.5 hrs even with the pre-boiling included. Pretty much the same as before (sometimes less).
What is SMB?
SMB = NaMeta = Sodium Metabisulfite
KMB = KMeta = Potassium Metabisulfite
Found either in powdered form or in tablet form (Campden). It’s used in this context as an Oxygen scavenger.
Thank you
How about a combination of yeast and preboil methods? Say half the regular amount of yeast/sugar for 30 minutes and heating to 85C? This could reduce time and energy. Does anyone have any yeast/sugar/time vs DO ratios?