DO Meter Surprise

[Brody]

I'm doing a side by side today with the Helles - One with SMS and scavenged strike water, the other without.

I just took a reading on the hi-oxygen wort after lautering... it's super low. Like the same ~0.5ppm reading I'm used to on lodo batches. What the fuck? Could it be that the 170f mash out is driving off a ton of O2? Or are these meters basically worthless for hot side purposes? I'm wishing I took a reading after mash in when it was in the 140s.

[Brody]

http://www.cotf.edu/ete/images/modules/ ... fPICT1.gif

Seems like the temp may play a major role - this chart doesn't go anywhere near the 76c mash out temp. I wonder if things would be different if I read after dough in?

This has me wondering, wether it's temperature caused or meter caused, if these meters can even be used as a useful indicator on the hot side. I mean basically 0 difference between a beat up mash and one protected like a baby is blowing my mind.

The real test will be in the taste and color though.

[Brandon]

[Bryan R]

Why even bother reading both. Your oxygen reading on the "high" mash is going to whatever o2 saturation the water can hold at your dough in temp. Meaning that, if you didn't de-oxygenate the water, the water will hold whatever amount of o2 it can at whatever temp the water is. You can't add more than that, only take away from it. The problem is even though at mash out and boiling your o2 saturation is low, but the damaging effects of oxidation have already been done. If this wasn't the case, then books and equipment manufacturers built around low o2, wouldn't be a thing.

[Techbrau]

The meters aren't good up to 76c.

[Brody]

Well... there's this: Any guesses on which is which? This is paper + 3.8% Dark Munich.

IMG_5056.JPG (2.08 MiB) Viewed 5050 times

[Bryan R]

Let me guess.... The one on the left is an "aha special" and the one on the right is brewed properly.

[Brody]

[Owenbräu]

Nice comparison.

Don't forget the compounds that we enjoy as flavor are also antioxidants, so they will scavenge O2 as well. The DO reading should be low. Our goal is to have the SMB scavenge O2 and preserve the malt compounds, but the O2 will be scavenged one way or the other.

[Brody]