Tilt Accuracy Testing - Interlude

Sometimes things don't work according to plan. Sometimes these also become learning opportunities! Unfortunately, I've had a number of these as part of my Tilt Hydrometer accuracy experiment.

Apparently yes, yeast expires

So I started "Phase 2" last weekend, but - as of Tuesday - had only seen the gravity drop from 1.078 to 1.075. Although it was dropping, the fact I hadn't seen more activity made me nervous. I ordered some Lalvin 71-B to supplement which was apparently enough of a threat to the Oktoberfest yeast it decided to wake back up on Wednesday and start doing its job – or so I thought. Fast forward a few more days, and by Sunday - 8 days into fermentation - the gravity was only at 1.064. Time to pitch some (additional) yeast!

Apparently yeast also produces CO2

The DMA35 measures density using an oscillating U-tube which vibrates a tube containing the sample in order to measure the sample's specific gravity. As it turns out, this vibration is amazing at - amongst other things - causing any CO2 contained in that sample to come out of solution and collect inside the U-tube.

Unfortunately, this significantly impacts the gravity readings:

Yeah. I highly doubt that this mixture fermented down to 0.896 in the past two days. I should have known that this was going to be a problem as I've had to use various degassing strategies for fermented beer in the past, but for some reason I didn't think it would be an issue in fermenting beer. Naive, I know.

My solution this time was to leverage a Ball jar and a jar sealer. Sanitize the jar, fill it with some "wort", shake the hell out of it, then use the "sealer" to create a partial vacuum. Let the bubbles settle, and we're in business!

Yeah - 1.066 seems far more reasonable.

Anyways - all of these are minor setbacks, as delayed measurement of a slow ferment doesn't impact the accuracy of a Tilt. The official "Part 2" coming soon!