Stuck ferments and ways to fix them.

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Stuck ferments and ways to fix them.

Postby bluc » Mon Sep 25, 2017 7:51 pm

Stuck Ferments and ways to try and fix them.

For a healthy ferment yeast needs a combination of the correct ph, nutrient (food) and correct temperature. Lack of any one, or in the case of temperature to low, it will slow the ferment to a crawl and may well even stop completely.
Ph is measured on a scale of 0-14. 0 being very acidic and 14 being very alkaline, a reading of 7 is neutral. Ideal starting ph for fermentation is about 4.8-5.5 a wash will usually stall if its starting ph is 3 or less. If you have really alkaline or “hard water” adjusts it using methods listed below.
A ph meter is a handy tool that can be used to measure ph so it can be adjusted if need. These very in price from $10 right up to 100’s for laboratory quality meters. At our hobby level a cheap $10-$50 meter will be more than adequate. If you find a meter for more than this with extra features you want, like maybe its water proof than by all means purchase it. Really up to you but the basic cheap ones will get the job done.

Adjusting ph

Adjusting ph is done a number of ways.

a) To raise the ph, make it less acidic, an alkaline substance is needed like calcium carbonate (lime) available from health food stores, your local pharmacy or even from your local home brew shop. I believe there is a horse feed grade calcium carbonate which should be available where you buy cracked corn or horse feed. Its also available as dolomite fertilizer personally wouldn’t use it either although it’s probably fine, up to you to do the research if you plan on using dolomite. Sea shells like oyster shells from your last feed of oysters.(BE SURE TO SCRUB WELL THEN BAKE WELL IN THE OVEN TO REMOVE ANY ORGANIC MATERIAL) or shell grit chicken feed from your local horse feed supplier. Also egg shells can be used. They need to be thoroughly baked in the oven to remove organic material and then ground to a powder. These will all raise the ph to a more suitable level. You can also use bicarb soda but after researching it has been mentioned by distillers it can leave unwanted flavors.
b) To lower the ph or make it more acidic an acid is needed. For a hobby level the easiest and safest way of doing this is by using boiler waste from an alcohol run also known as “Whiskey Backset” or “Rum Dunder”.

If doing neutral sugar or grain wash the boiler waste can also be used it’s exactly the same acidic liquid as dunder or backset.

Don’t put rum dunder in a whiskey mash and vice versa as it will alter the flavor. Unless you want to experiment, and that’s fine to.
For either raising or lowering ph do it in small amounts taking regular readings till you reach desired amount. As a ball park figure I put a cup of calcium Carbonate in 200l wash.
c) Dunder/backset is also used for flavor if you want to add more of it then needed to adjust ph simply add some alkaline substance to bring the ph up to 4.8-5.5ph.

Yeast nutrient

Ok so you adjusted ph but the mash/wash still not fermenting? Try to add some yeast nutrient. An example of yeast nutrient is D.A.P or “Diammonium Phosphate” dosage is up to max 5g per 5l. There are other nutrients available and your home brew shop could probably help with this.


Ok so the ph and yeast nutrient are taken care of have a look at your fermenters temperature. Yeast comes in a wide range of types and suitable temp ranges for them are usually written on the packet. Too low a temp for the yeast and the yeast will go to sleep and your brew will stop fermenting. Too hot and it can create unwanted esters (flavors). Some examples of keeping heat in are wrapping the fermenter in insulation maybe a doona/blankets or using an aquarium heater is another popular way of keeping fermenters warm. Unfortunately cooling can be more tricky unless in a cold climate area. With small fermenters a fridge can be used.

Ok so that is about it, I hope someone finds it useful.
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