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View Full Version : Am I in Danger of a stuck/stalled ferment?



dougmedic
04-25-2008, 10:31 PM
I've been working on a batch of Orange-spice Meth, but I'm afraid my ferment is stalling or stuck. I'm not sure if it is a bad recipie, bad yeast choice, not enough nutirient, or what...

I been able to keep the ferment temp a fairly steady 24-25C. Lavlin KV1-1116 should be ok until approx 16%ABV alcohol toxicity, and if by gravity I should be around 10%ABV, so it shouldnt be that, right?

So what might be causing my ferment to stall?

Thanks,
Douglas

Orange Spice Methglyn
Must Type: Honey, grape concentrate
Batch Size 25 litres

Fermentation Start Date: Apr 13, 2008
Yeast: Lavlin KV1-116

Additions
Apr 13, 10 gm Lavlin KV1-1116 (yeast, active dry)
Apr 13, 15 gm Bentonite (Rehydrated and added to must)
Apr 13, 1 L Riesling grape concentrate
Apr 13, 9 kg Alfalfa-Clover Honey
Apr 13, 60 gm Orange Zest (dried, grated)
Apr 13, 1 tsp@ DAP & Yeast Energizer (before innoculatoin)

Apr 14, 3/4 tsp Yeast Nutrient
Apr 14, 1/2 tsp Yeast Energizer

Apr 17, 1/2 tsp Yeast Energizer (1/3rd sugar break)
Apr 17, 1/4 tsp Yeast Nutrient & (1/3rd sugar break)
Apr 18, Removed Orange Peel bag

Measurements
Date Sugar Temp.
Apr 13, 1.120 27 C
Apr 15, 1.104 24 C
Apr 17, 1.080 25 C
Apr 18, 1.066 25 C
Apr 19, 1.060 26 C
Apr 21, 1.052 25 C
Apr 22, 1.050 24 C
Apr 24, 1.046. 25 C
Apr 25, 1.046. 25 C

Medsen Fey
04-26-2008, 11:55 AM
Have you checked the pH?

dougmedic
04-26-2008, 12:22 PM
Have you checked the pH?

Since I have no access to lab or test equipment, is there a relativly simple way to do this?

Thanks,
Doug

wayneb
04-26-2008, 01:34 PM
Hand-held or "pocket" pH meters are available for a reasonable cost from most chemical supply houses or brewing supply shops. They are the easiest way to check pH with a reasonable accuracy.

If you can't easily acquire the ability to monitor pH, adding approximately 6 g of potassium carbonate or potassium bicarbonate (pre-dissolved in a little water) to your must will not hurt it, and if pH is the issue that may be enough to re-start fermentation. It is also possible that the yeast did not have access to enough oxygen early in their lifecycle. Did you aerate the must before pitching? Also, did you rehydrate the yeast according to Lallemand guidelines, or did you simply pitch dry? We could ask many more process questions, so to save time could you outline the steps of your process in more detail?

Brad Dahlhofer
04-27-2008, 09:08 AM
You can order pH strips online if you don't want to spend the money on an electronic PH meter. Make sure you get the type that are for wine since they only have a narrow range that will make reading easier. You should also pickup some Potassium Carbonate (as WayneB suggests) because that's very likely your problem. Looking at your recipe, I'm thinking your pH is pretty low. I like my meads to be right around 3.8.

Also, what is the room temperature where you're fermenting?

dougmedic
05-04-2008, 01:38 PM
This was my process:

Rehydrated 15gm Bentonite in boiling water.
Added grape concentrate & honey to 30C temp water.
Mixed well and took initial SG 1.120 @ temp of 28 C
Added nutrient - 5gm each DAP & generic "Yeast Energizer"
Aerated with "wine-whip" for 5 minutes.
Added dried orange peel/zest in a strainer bag.
Pitched 10gm of Lavlin-71B yeast (rehydrated per mfg instructions).

Ferment temp has been between 24-25 C consistantly.

SG progress:
Apr 13 - 1.120 (initial)
Apr 17 - 1.080 (1/3 break)
Apr 19 - 1.060 (1/2)
Apr 30 - 1.040 (2/3)
May 02 - 1.038

I managed to get some pH testing stuff... not the best though.
The test kit that i got at first had both liquid reagent tests, and a quick-strip, but only covered pH 4.5-9. These two test showed it had to have been below 4.5 as it didnt even register.

A friend had some two-three year old orange litmus paper strips that were supposed to cover pH 1.5-8. Using that it looks (by the colour chart) like the ph is between the colours for 1.9 & 2.2, if the strips are at all still accurate.

wayneb
05-04-2008, 06:30 PM
In my experience with those strips, when they get old they react less, and tend to read around 3.5 regardless of the actual pH of the liquid under test. Since you're showing pH in the neighborhood of 2.2, if you are reading the strips correctly, the pH of your must is way too low to sustain fermentation. Actually, those wide-range strips are only accurate to around one full pH point, so a reading of 2.2 could be had from a liquid ranging in true pH from 1.2 to 3.2. Just for your reference, standard dilution distilled white vinegar is on the order of pH 2.4-2.5, and you're likely in that neighborhood.

With a pH that low, I recommend the addition of potassium carbonate or bicarbonate without reservation. You might not be able to get this batch restarted after the pH is brought back into the optimal range of 3.5 to 4.0, even with the addition of a more robust yeast such as EC-1118, but if you want it to go drier it is still worth a try.

If you use K-carbonate to adjust the pH, don't add any more than enough to move the indicated reading by about 0.5 at a time. Then allow the must to rest for a day and re-test. pH equilibrium in a mead must depends on several factors that interact with each other and equilibrium takes a little while to settle out.