Root Vegetable, Rice, Amylase and Yeasts

[Moebius]

When wine is made from root vegetables such as potato and parsnip (and also rice) I assume that even though sugar is added, the starch content of the main ingredient is also used to some extent. Conversion of starch to alcohol depends on the presence of amylase to convert it to sugars which can then be utilised by the yeast.
So -
1 Presumably adding amylase first would be a good idea, but so far I haven't seen it included in receipes.

2 Does baker's yeast contain amylase as I feel that this helps the bread making process?

3 As bakers yeast presumably will not be as efficacious as proper wine making yeast why not use both together?

I can remember that when my father made wine (about 50 years ago!) he always used bakers yeast as that was all that was available at the time, usually to make potato wine, and these always seemed to be pretty potent.

 

[Luc]

3 As bakers yeast presumably will not be as efficacious as proper wine making yeast why not use both together?

I can remember that when my father made wine (about 50 years ago!) he always used bakers yeast as that was all that was available at the time, usually to make potato wine, and these always seemed to be pretty potent.

So you already gave the answer. Bakers yeast is indeed as good as winemaking yeast it is only different in some aspects of the winemaking process. But it can be used.

There is however a problem using 2 yeast starins at the same time.
One strain might have a 'killer' instinct. This means that the yeast produces some enzymes that actually inhibit or kill other strains. So in using a cultivated strain together with bread-yeast the cultivate strain might actually kill the bread yeast. And therfore the initial intention would be made useless.

I have however no idea on how the starch would be transformed.

However each lhbs will sell amylase so why not add it anyhow.

Luc

 

[Moebius]

yeast reply

Thanks for the comments Luc.
Invasion of the killer yeast!!!!
I usually use a general purpose, high alcohol yeast sold here in the UK as SB3 which is supposed to get as high as 15%. Some references say bakers yeast will only get to 5%, others that it will reach maybe 10-12%.
I guess that as you say I should try it and see what happens, so next batch will be a potato wine.
As a retred chemist I can calculate the conversion rate of sugar to alcohol and I am trying to see how the total calculated sugar content results in sweetness. So far the results have been completely meaningless! I think the problem has been variation in fermentation temperature as I was brewing in the garage. Now I have managed to persuade the good lady to let me keep the fermentation bottles in a wardrobe, so we shall see if this improves things.